Dynamic Language Use in Bi/Multilingual Early Childhood Education Contexts: A Critical Review of the Literature

The population of students learning and using more than one language in the United States has more than doubled in the past 30 years. This is especially true in early childhood, which makes it crucial that educators of young emergent bilingual children understand and support these young children’s bi/multilingual development, including critically understanding the implication of adopting different perspectives of bi/multilingualism. Although much is known about classroom practices in support of emergent bilingual children in Kindergarten and beyond, less is known about those practices in the early years. This article provides a systematic review of relevant qualitative empirical studies that investigated teachers’ and children’s naturalistic language use in bi/multilingual early childhood education settings. The authors identify several strategic languaging practices enacted by both teachers and children across different language approaches, and strategies for fostering these practices; as well as ways in which teachers leverage their agency through their languaging practices depending on the language policy of each program. Implications for future research, practice, professional development, and policy are discussed.


Introduction
The population of students learning and using more than one language in the United States has more than doubled in the past 30 years (García & Kleifgen, 2018;OELA, 2017). As such, the number of young emergent bilingual (EB) children, including those in early childhood

Researcher Positionality
Ryan identifies as a bilingual white male. Although he grew up in a monolingual and monocultural region in the Northeastern United States, he has since resided in multilingual, multicultural areas that have come to feel more like home. A former two-way dual language elementary school teacher introduced to and aligned with policies of strict language separation, he currently researches and advocates for the leveraging and use of flexible bilingualism.
Ivian, raised in Brazil in a monolingual middle-class environment, identifies as Latina and bilingual. She became a literature teacher and textbook author, and pursued a bachelor's degree in education. Later, as a mother, she immigrated to the U.S., learned English, and completed a master's degree dedicated to understanding literacy in heritage languages in the U.S. During the course of her Ph.D. studies, she started to question why heritage languages have typically been discussed as a family policy matter, and in what ways monolingual ideological discourses frame language policy and curriculum in multilingual settings.
Lergia identifies as a U.S.-native bilingual English/Spanish Hispanic female born of two middle-class parents who permanently emigrated from Cuba during the start of the Castro regime in the early 1960s. Throughout her childhood and early adulthood, she was immersed in a multilingual community, both at home and in the public school educational environment. Her studies in English (B.A.) and Linguistics (M.A.) kept her close to her passion for natural bilingualism and the benefits of fluency in multiple languages. She is currently a doctoral student pursuing a degree in Teaching and Learning, and is married and raising a bilingual son.

Bilingualism as a Construct
In this literature review, we situate our conceptual framework within the work of critical scholars. Because bilingualism is a social construct related to assumptions around citizenship, language, and the state (Stroud, 2007), it is crucial to recognize how, historically, the phenomenon of bilingualism has been situated within discourses linking languages to political authority and legitimacy (Heller, 2007). Because this notion of bilingualism is tied to ideas of monolingual nation-states, we aim to understand what it means to be bilingual in a multilingual 1 Head Start uses dual language learner, and education agencies often use deficit-based terms such as English language learner or limited English proficient. classroom, what practices teachers and children use in this context, and what practices are valued in these early schooling experiences. We specifically direct our efforts to understanding bilingualism as a phenomenon in one educational context: bilingual programs in ECE, with a focus on investigating and discussing the instructional strategies most valued in the focal studies as they relate to the language policies in place. We define bilingual programs as those that intentionally use two or more languages for learning purposes.
Bilingualism is a phenomenon currently studied from a multidisciplinary perspective including linguistics, psychology, sociology, and anthropology. However, Heller (2007) and Stroud (2007) noted that research on bilingualism started with Weinreich's (1953) descriptive study of bilingualism in Switzerland, highlighting "how one grammar may influence another, and what kinds of conditions (mainly social, but also psychological) might explain why things look one way or another" (pp. 6-7). The focus on describing linguistic systems was also evidenced in Mackey's (1968) similar work on typologies of bilingualism and Fishman's (1968) conceptualization of variability across domains. In the following forty years, scholars predominantly used this structural-functional paradigm in which languages were understood as a whole, bounded system, associated with whole and bounded communities. This paradigm of bilingualism research predominantly focused on measuring universal patterns, discovering the links among languages, and discussing their social and psychological conditions. This assumption of languages as bounded systems implicated the predominant focus on linguistic systems as connections, leading to more recent research on "code-switching," which has been used to test linguistic theories. Recently, scholars (e.g., García & Wei, 2014;Heller, 2007;Pennycook, 2010) have problematized the idea of language as a bounded system related to the assumptions of territories and ideological discourses of nations and states since the 19th century. Consequently, the notion of bilingualism as two separate languages each consisting of a bounded structural system has been called into question.

Perspectives of Bilingualism
Framing our analysis in the idea of bilingualism as a social and historicized construct, we highlight two dominant perspectives of bilingualism in current research: one more traditional, which views languages as discrete systems, and the other more holistic and dynamic. In the following paragraphs, we situate these perspectives. A traditional perspective: Bilingualism as additive/dual. A traditional perspective of bilingualism views languages as separate entities, sometimes interconnected. As such, the goal is that bilingual students develop balanced bilingualism, wherein each language has the same (high) level of proficiency. Consequently, each is understood as an independent language system to be mastered. This perspective includes the notion that bilingual learners initially appropriate ideas, concepts, and skills in one named language and then have the potential to transfer them to an additional language, since all learning is understood to be part of an underlying repertoire of knowledge (i.e., Common Underlying Proficiency; Cummins, 1981), though the languages themselves are considered finite and discrete. By viewing languages as separate entities to be mastered, educators often expect students to perform with monolingual-like proficiency in each language, an expectation that can lead educators to evaluate EB students as deficient (García & Kleifgen, 2018;García & Otheguy, 2020). Holistic models: Bilingualism as dynamic. In contrast to this traditional and additive perspective of bilingualism, a dynamic perspective draws on the belief that different government-and socially-named languages (e.g., Arabic, Haitian Creole) comprise one dynamic linguistic repertoire, housed within a single system. This perspective views language as a verb, thus highlighting the ever-evolving nature of the complex and natural social practices in which bilinguals engage. Using their single language system, speakers move fluidly among multiple languages, dialects, and modalities in their everyday interactions (García, 2009;García & Leiva, 2014;Wei, 2018). This is what we understand to be naturalistic languaging practices, or translanguaging, where speakers challenge the monolingual norms that society has imposed on them, showing that bilinguals are not two monolinguals in one (Grosjean, 1989). In these models, the bilingualism that they develop is a dynamic phenomenon that is seen in a holistic way to better reflect the fluid and complex relationships among different languaging practices (García & Wei, 2014). These differing perspectives of bilingualism influence the language policies that are created and upheld in different learning environments. Although language policies reflect the perspectives of bilingualism discussed above and outline the expectations for language use in each program, how teachers create and operate within specific language policies vary. Understanding language in this way supports educators in viewing EB students' language performances as natural, creative, and intelligent, not lacking (García & Kleifgen, 2018).

Language Policies in Bilingual Education
Contributing to teachers' use of various bilingual practices are both the language policies that programs establish and teachers' own language ideologies. Language policies serve to promote a desired, and often national, language (Wiley, 2015). In schools, these policies naturally involve teachers, leading to them having a major role in promoting national languages and in implementing language policies (Wiley, 2015). Below we provide a brief outline of U.S. language policies for different bilingual education programs to shed light on those that exist and the confines within which teachers are expected to operate. We begin with K-12 and then turn to ECE to highlight the influence the former has had on the latter.
In K-12 bilingual education, there are three generalized approaches to using students' home languages. García & Kleifgen (2018) report that students' home languages are used either to transition to English or to develop bilingualism and biliteracy. Language policy for transitional bilingual education typically states that home language use is expected, allowed, and serves the purpose of providing "English learning" students with enough content knowledge until they are capable of performing academic tasks only in English. Policy requires that teachers move students as quickly as possible from using mostly/all home language to all English. In a second approach, language policy for developmental and dual language bilingual education articulates purposeful use of English and a partner language (e.g., Spanish) to teach academic content (i.e., math, science, language arts, history/social studies). How much of the partner language is expected to be used is also dictated by the policy (e.g., 90/10, 50/50). Moreover, whether official or unofficial, there tends to be a policy of language separation in these contexts. This is accomplished by allocating instruction in each language to a time of day, a space (i.e., a particular classroom), or a teacher. The focus is on standardized/dominant usages of two separate, discrete, and static national languages: English and the partner language García & Kleifgen (2018) also highlight a third approach, dynamic bi/multilingual education, wherein the language policy stipulates "English and students' home languages in dynamic relationship; students are the locus of control for language used" (p. 33). In other words, the focus is on language as flexible and ever-evolving, not as one (or two) discrete and static national language(s).
In ECE, the Office of Head Start (n.d. a), a leader in the policy field, has adopted the Planned Language Approach, "a comprehensive, systemic, research-based way for Head Start and Early Head Start programs to ensure optimal language and literacy services for children who speak English and for those who are dual language learners (DLLs)" (Planned Language Approach section, para. 1), which includes specific classroom language models (Head Start, n.d. b) that outline accompanying language policies largely built on those from K-12. Those models include English with Home Language Support (EHLS), Dual Language (DL), and Home Language as a Foundation for English Development (HLFED). In the EHLS model, intentional support is provided to "dual language learners" (DLLs) for a variety of purposes, including comforting children, exploring books, and interacting with environmental print, among others. Like transitional bilingual education in K-12, the focus is on English as a national language. In the DL model, both languages are intentionally used for instruction, all children (English speaking and DLLs) are expected to develop bilingualism, and "each language is spoken during designated, equal, and predictable periods" (Head Start,n.d. b,p. 11,bold in original), requiring a separation of languages. This is akin to two-way immersion models in K-12, although Head Start does not require equal numbers of English speakers and DLLs. Like the K-12 developmental bilingual education model, in the HLFED model, the home language is used for instruction and communication, and English is gradually introduced. In each case, the expectation is that everyone involved strictly adheres to the stated language policies, which, for DL, means language separation. However, outside of Head Start, there is very little consensus on--or even talk of--how to characterize ECE programs that use two or more languages. This is reflected in a lack of consistency of terminology (i.e., labels such as "two-way immersion," "transitional bilingual education," or "ESOL" are rarely used in ECE literature).
Given the boundaries that each language policy draws, how teachers navigate the tensions between language use (and separation) and its practical realization (Gort & Sembiante, 2015) may provide key insights for teachers, administrators, and other policy makers at multiple levels. Thus, dynamic languaging and resistance in school, including how teachers' and children's language use is restricted/suppressed or validated/supported by policies and practices that shape bilingual education and language immersion programs, is a factor that must be investigated and understood to enhance the knowledge base of the field. This critical review of the literature took special consideration of these policies and contexts as we systematically explored teachers' and children's languaging practices. Specifically, we investigated the following questions: • In what naturalistic languaging practices did teachers and children engage in bi/multilingual early childhood education contexts? • How did those practices conform to the language policies? We now provide a detailed methodological description of our search process.

Data and Method
The goal of this literature review was to identify work conducted in typical ECE contexts (i.e., center-based childcare, family childcare 2 ) to shed light on teachers' and children's dynamic 2 Child care provided by a licensed professional in their home (National Association for Family Child Care, n.d.; Florida Department of Children and Families) languaging practices as related to multiple language policies, present a systematic synthesis of relevant studies, and provide directions for future practice and research. We followed Boote and Beile's (2005) framework for critical literature reviews to ensure a high level of rigor.

Inclusion/Exclusion Criteria
To determine the most pertinent set of research to review, we purposefully defined both inclusion and exclusion criteria. Our interest was in naturalistic languaging practices in ECE contexts, which required a focus on teachers/providers and children 0-5 years old 3 . We wanted to ensure a trustworthy set of high-quality empirical studies, thus leading us to include only peer-reviewed journal articles. As such, specific inclusion criteria included: (a) qualitative empirical studies, (b) articles published between 2005 and 2018, (c) articles published in double-blind peer reviewed journals, and (d) articles in which child participants were 0-5 years old. Exclusion criteria included: (a) dissertations, (b) book chapters, (c) articles not written in English 4 , (d) articles focused on monolingual instruction, (e) articles where child participants were in Kindergarten or higher grade levels, (f) articles where the research did not take place at a school or school-like setting (e.g., research laboratories or home case studies), and (g) articles that used an experimental design.

Literature Search
Our research for this literature review began with a search of four databases, specifically PsycINFO, PsycARTICLES, ERIC, and Google Scholar. We first used the following search terms, either individually or in some combination: "instruction," "preschool," "translanguaging," "child," "early childhood education," "bilingual," "dual language learner," "dual language 5 ," "code-switching," and "pedagogy." After duplicates were removed, these searches yielded 125 scholarly articles, book chapters, dissertations, and other publications. When we applied our exclusion criteria, 11 articles remained. From these 11 articles, we thoroughly read and examined each, beginning to establish recurring themes throughout the literature. After this initial research, we used the reference sections of relevant articles and dissertations of the 125 original sources to find additional articles that met inclusion criteria but had not surfaced at first (Wohlin, 2014). We also searched once again in the databases for articles that had been published since our initial search three months prior or not initially found, this time using only the specific search combinations "translanguaging + language practices" and "translanguaging + preschool." This process provided us with an additional 41 sources, and after applying exclusion criteria, we included an additional 18 articles in our corpus, for a total of 29 articles that became the data used for this literature review.

Approach to Research
3 Although ages 0-8 are commonly accepted as early childhood, we focus on 0-5, acknowledging that 90% of brain development occurs in this time period (Center on the Developing Child, 2016; Lenroot & Giedd, 2006), making it a foundational time to recognize and support multiple language learning. 4 This is a limitation of the authors' own linguistic repertoires. 5 The term "two-way immersion" was not included since it is often used interchangeably with "dual language." Furthermore, given the lack of agreement or use of terms describing bilingual education in ECE, we relied on "dual language" since it is widely used by Head Start.
Our approach for this literature review was both inductive and deductive. While knowing a priori that we were considering teachers' flexible languaging practices and how those practices were enacted within differing language policies, we also employed an opencoding process to chunk areas of convergence across the literature (Corbin & Strauss, 2008. We reviewed convergences and identified two overarching themes: (a) the diversity of naturalistic dynamic languaging practices in ECE contexts and (b) teacher agency within language policies. We then returned to the focal studies and coded for patterns and subthemes to help us understand and explain the two themes (Tieken & Auldridge-Reveles, 2019). We honed in on findings with support across multiple studies, as well as any contradictory evidence, although none was found. This approach is used more commonly in qualitative research, where researchers start with more general questions and use their findings to navigate their conclusions. In fact, to "code" data and compare categories in service of generating thorough explanations can be a meticulous process (Kamberelis & Dimitriadis, 2005).
Studies described a variety of early learning programs, approaches to supporting language development, and language policies. Along with the geographical location of each study and the languaging practices of teachers and children, this information is detailed in Table  1. Approaches to supporting language development included: (a) Specifically-structured bilingual programs (e.g., dual language, two-way immersion), (b) Unspecified bilingual (i.e., studies stated explicitly that the program was bi/multilingual but did not follow a predetermined approach such as dual language), and (c) Bilingual-in-practice (i.e., the program did not refer to itself as bilingual, but teachers either were told they could interact bilingually with children or chose to on their own). Language policies either supported flexible bilingualism (i.e., teachers were permitted to draw on features from more than one language at a time) or required language separation (i.e., teachers were expected to use only one language at a time).

Results
Below, we outline our findings in terms of two salient themes that emerged from the focal studies. We first address the diversity of languaging practices observed from the participants, and then discuss varying degrees of agency observed in both teachers' and children's language use.

Dynamic Languaging Practices in ECE Contexts
All 29 studies included in this literature review contributed to an understanding of teachers' and/or children's naturalistic languaging practices in ECE contexts. That is, neither teachers nor children were bound by research design (e.g., quasi-experimental) to "perform" language in a specific way. In the focal studies, teachers and children were observed to overtly enact dynamic languaging practices across a range of learning contexts and highlighted strategies for fostering those practices. Below, we elaborate more pointedly on these distinctions.

Dynamic Languaging Practices across Specific Learning Contexts
Across all three approaches to supporting language development (specificallystructured, unspecified, and bilingual-in-practice), teachers regularly promoted and/or engaged in dynamic languaging practices, even when language policies called for language separation. Moreover, various dynamic languaging practices were documented within multiple learning contexts, including sociodramatic play (i.e., "play that involves the acting out of scripts, scenes and roles" [Bengochea et al., 2018, p. 39]), unstructured playtime, show-and-tell, and read alouds. These practices showed that "acknowledging and supporting diversity in the classroom contributes to the cultivation of a positive emotional environment" (Baker, 2018, p.13).
During sociodramatic play in a dual language program, Bengochea et al. (2018) observed how four-year-old Anthony drew on multimodal resources, including translanguaging, depending on his play purposes and interlocutors. That is, he translanguaged with his peers and performed in monolingual English with his teachers, even engaging in a parallel monolingual English conversation with his Spanish model teacher. These exchanges highlighted the complexity of Anthony's languaging, and therefore, the importance of young EB children drawing on different modes and languaging practices to amplify their experiences. In a twoway immersion program where teachers were expected to adhere to a policy of language separation, Schwartz and Deeb (2018) also found that during sociodramatic play activities, children-led conversations had richer exchanges as indicated by greater frequency of productive language and fewer formulaic utterances.
In specifically-structured (Alanís, 2018;Schwartz & Deeb, 2018), unspecified bilingual (Axelrod, 2017), and bilingual-in-practice approaches (Boyd et al., 2017), children's language practices during structured (i.e., teacher-led) and unstructured (i.e., children-led) playtime learning contexts were analyzed. Teachers allowed--and children engaged in--translanguaging, thereby positioning children's full linguistic repertoire as a resource and working to support children's capacity to imagine, create, and regulate their own learning as well as other students' behavior. For example, Axelrod (2017) described four-year-old Soraya engaging in complex exchanges: She would often engage in translanguaging, for example ''I'm gonna play in the cocina (kitchen)'' and would mix in words and phrases, such as muchacho (boy) Ay dios mio (oh my God) into her speech. She often played with language and would use a lot of idioms in both English and Spanish. Her language usage and vocabulary was complex and she often used phrases that seemed more ''adult-like,'' and would often take on phrases that she heard adults using. (p. 107) In a study of teachers' and children's languaging during show-and-tell in a specificallystructured bilingual program, Gort and Sembiante (2015) found that while co-teachers' languaging practices mostly followed the one-teacher-one-language policy, children's language choices were not regulated, and they felt free to draw on their full linguistic repertoire. In this case, teacher's translanguaging predominantly served to reaffirm students' oral production, redirect behavior, provide academic vocabulary, ask students questions for clarification, and expand initial information. Gort et al. (2012), in their study of a specifically-structured bilingual program, investigated the nature and distribution of dual language preschool teachers' questions across read alouds in English and Spanish to understand how teachers' questions supported learners' meaning-making, ultimately identifying an inequitable distribution of questions and opportunities for extended dialogue across target languages. Specifically, during Spanish read alouds, although children were asked questions requiring them to draw a conclusion more often than during English read alouds, there were more questions requiring information recall in Spanish read alouds, resulting in less conversation in that context. They suggest that teachers strategically develop and plan to ask a variety of questions in each target language with sufficient support for children to dynamically develop their bilingualism to include monolingual and bilingual performances.

Strategies for Fostering Dynamic Languaging Practices
Focal studies not only highlighted teachers' and children's languaging practices as naturalistic and useful communication within learning contexts, but they also shed light on strategies for cultivating these practices, including creating and fostering a comfortable environment in which to language freely, encouraging children to play with language, and modeling various translanguaging practices.
Creating and fostering a comfortable languaging environment. Providing a comfortable atmosphere inviting and supporting children's use of their full linguistic repertoire, including children's translanguaging, aided in the execution of activities across all approaches to supporting language development (Alanís, 2018;Baker, 2018;Bengochea et al., 2018;de Sousa, 2017;Gort & Sembiante, 2015;Kim, 2016aKim, , 2016bKirsch, 2018b;Pontier & Gort, 2016;Schwartz & Deeb, 2018). For example, children's multimodal interactions, including translanguaging, helped include peers in activities, as was the case when two boys shifted from a passive to a more active role during their group conversation when they drew on their full linguistic repertoire to support their meaning-making process in a bilingual-in-practice program (de Sousa, 2017). In another bilingual-in-practice program, Kim (2016b) similarly found that, when allowed to use both Korean and English when they had discussions about books with their peers, children translanguaged and expressed their views comfortably, providing them with opportunities to explore diverse perspectives about the books they read and fostering "literary understanding, critical examination of texts and deep engagement with more advanced thoughts" (p. 332). Axelrod (2017) found in an unspecified bilingual program that teachers' encouragement of multilingual learners' play with words while drawing on their full linguistic repertoire and interacting with each other is a fruitful strategy that supported a "dynamic cycle of multiple language development, understanding that part of the process of developing language is playing with language" (p. 109), which also leveraged their understanding of how language works.
Modeling translanguaging practices. Teachers themselves sometimes engaged in strategic translanguaging (Kirsch, 2018a(Kirsch, , 2018bPalviainen et al., 2016;Pontier & Gort, 2016), thereby modeling dynamic languaging practices for children. This was the case when, for example, teachers negotiated with children in an unspecified bilingual program (Palviainen et al., 2016), participated in shared book readings in a specifically-structured bilingual program (Pontier & Gort, 2016) or interactions with and around technology in an unspecified bilingual program (Kirsch, 2018a), and supported children's vocabulary acquisition (Kirsch, 2018b). Moreover, teachers embraced, accepted, allowed, and supported children's translanguaging (Axelrod, 2017;Gort & Sembiante, 2015;Kirsch, 2017;Palmer et al., 2014). In enacting these practices and making space for them, teachers highlighted the value of dynamic languaging practices. In many instances, teachers made knowing choices to language bilingually, regardless of the existing language policy. In the next section, we further explore teachers' agency in contexts with differing language policies.

Teacher Agency
Teacher agency, determined by teachers' knowledge, skills, abilities, and personal and professional beliefs (Boyd & Ottesjö, 2016;Kim, 2017;Kirsch, 2017Kirsch, , 2018bMifsud & Vella, 2018;Palmer et al., 2014, Palviainen et al., 2016, played an important role in bi/multilingual ECE contexts. Using a combination of these factors that characterize agency, teachers made purposeful decisions and took meaningful action in the classroom. Specifically, as we will discuss in further detail below, ECE teachers purposefully either adhered to or contested institutionalized language policies, showing strong underlying ideologies about flexible languaging practices as they exercised their agency. As such, teachers were policymakers in their own right (Menken & García, 2010), based on whether or not they allowed children to draw on their full linguistic repertoire. Teachers' agency became salient, therefore, in the contrast between strict language separation policies and the natural social interactions of bilinguals, often revealing a mismatch of learners' linguistic behavior (and realities) inside and outside the classroom. Teachers' enactment of their agency existed independently of classroom language context, as there was no clear pattern between the type of language model/policy and whether teachers aligned with or contested the stated policy.
Of importance is that when teachers engaged in flexible languaging performances, they valued the use of translanguaging in the classroom and positioned children as competent bilinguals (Gort & Sembiante, 2015;Palmer et al., 2014, Palviainen et al., 2016 capable of both understanding teachers' languaging practices and enacting their own languaging practices. Thus, although teachers were typically viewed as those exercising their agency, children were also observed as active agents of a wide variety of bilingual practices, contrasting with any monolingual practices of the staff in preschools (Boyd et al., 2017;Boyd & Ottesjö, 2016;Portolés & Martí, 2017).

Leveraging Agency through Languaging Practices Aligned with Language Policies
Some teachers followed and modeled language policies that advocated for flexible bilingualism (Alamillo et al., 2017;Axelrod, 2017;Palviainen et al., 2016;Puskás & Björk-Willén, 2017), while others imposed the schools' policy of language separation or monolingual policies (Alanís, 2018;Bengochea et al., 2018;Boyd et al., 2017;Gort et al., 2012;Puskás & Björk-Willén, 2017;Schwartz & Deeb, 2018), regardless of their personal beliefs, sometimes demonstrating a lack of responsivity to the dynamic language use of learners (Puskás & Björk-Willén, 2017). In cases where teachers' own languaging practices aligned with the official language policy of promoting flexible languaging practices, they allowed students to language freely while also doing so themselves (Kirsch, 2017;Mifsud & Vella, 2018). Kirsch (2017) highlighted this match between policy and practice, concluding that teachers in her study engaged in the government-endorsed legitimate practice of translanguaging to "capitalize on children's multilingualism and model and use multilingual and multimodal resources" (p. 160). This was also the case in Garrity and Guerra (2015), where the Head Start policy was that teachers should "support children's first language while helping them acquire oral proficiency in English" (p. 245). One of the co-teachers believed that both languages should be supported simultaneously in the classroom, and she and engaged in bilingual practices.
In other studies, teachers' beliefs and/or practice aligned with the school's promotion of a language separation policy (Alanís, 2018;Bengochea et al., 2018;Boyd et al., 2017;Gort et al., 2012;Mifsud & Vella, 2018;Schwartz & Deeb, 2018). For example, in one of the two focal schools with a language separation policy in Mifsud and Vella (2018), the teacher "did not legitimise the children's contributions in English and continually reminded the children that they had to use Maltese, even while working in groups" (p. 282). As such, the teacher reinforced the language separation policy at all times, precluding children from languaging flexibly.

Leveraging Agency through Languaging Practices that Contest Language Policies
Teachers also use their agency to contest language policies (Arreguín- Anderson et al., 2018;Baker, 2018;Boyd & Ottesjö, 2016;Gort & Pontier, 2013;Gort & Sembiante, 2015;Kirsch, 2017Kirsch, , 2018aKirsch, , 2018bMifsud & Vella, 2018;Palmer et al., 2014;Palviainen et al., 2016;Pontier & Gort, 2016;Portolés & Martí, 2017;Puskás & Björk-Willén, 2017;Schwartz & Gorgatt, 2018). Some teachers contested a language separation policy because they believed in the benefits of flexible languaging practices in the classroom (e.g., Palmer et al., 2014;Portolés & Martí, 2017). For instance, Baker (2018) found that teachers made a knowing decision to use children's home languages during guided play activities even when the expectation was to use English, a move that increased young EB children's sense of classroom belonging. Similarly, in Palviainen et al. (2016), teachers consciously reported having "made modifications over time--from previous use of a bilingual educational model built on language separation to a flexible bilingual model--and that they had done so actively and knowingly" (p. 621) in order to "negotiate differences in the children's linguistic backgrounds and emotional, cognitive, or social needs" (p. 627) and to help monolingual students better develop their languaging repertoire and understand the importance of minoritized languages.
However, the reverse was also true--other teachers contested a flexible languaging policy because they believed that a monolingual policy was best for the students. For example, in Puskás and Björk-Willén (2017), two of the focal teachers chose to language monolingually in their designated language despite national policy (extended to the particular preschool program) that could have been interpreted as an endorsement of flexible language use. Even in Garrity and Guerra (2015), despite a nebulous language policy, one of the teachers adhered to the language policy, but the other did not. She engaged in more monolingual English practices with the children and argued "that English should be taught at school and Spanish should be taught at home" (p. 252).
Top-down imposed monolingual policies often contrasted not only with the reality of teachers' flexible languaging practices, but also with the students' language behavior, which naturally steered toward use of their full linguistic repertoire (Alamillo et al., 2017;Arreguín-Anderson et al., 2018;Gort & Pontier, 2013;Kirsch, 2017). This contrast suggests a need to challenge rigid language separation policies (i.e., maintaining monolingual use of the target language) as best approaches to language education in ECE and to instead validate students' flexible bilingualism (Portolés & Martí, 2017). As such, teachers also contested rigid language separation policies. Similarly, in Palmer et al. (2014), the teachers challenged the rigid language separation policy and actively translanguaged along with the children, promoting the acceptability of translanguaging and encouraging students to use their full linguistic repertoire. In doing so, they became "models of dynamic bilingualism" (p. 763).

Leveraging Agency in Intentional Ways
Teachers in the focal studies made important adjustments in their languaging practices when interacting with children (Gort & Pontier, 2013;Gort & Sembiante, 2015;Palviainen et al., 2016), but they may have done so as a reaction rather than as a purposeful and preplanned teaching strategy. In other words, whether these shifts were made with intention or were always more organic and responsive is not yet entirely evident. When teacher interviews were part of the methodological approach (Palvianen et al., 2016), greater understanding of the teachers' behaviors was achieved, sometimes showing an intentional leveraging of their agency.

Discussion
This literature review focused on teachers' and children's naturalistic languaging practices in bi/multilingual ECE contexts. After engaging in a systematic search for relevant qualitative empirical studies and applying strategic inclusion/exclusion criteria, we were left with 29 focal studies. The study (a) provides a description of teachers' and children's languaging practices and (b) highlights teachers' agency in the act of either aligning with or contesting existing language policies in ECE contexts.
In addition to shedding light on numerous linguistic practices, findings of this systematic review of qualitative literature show that early childhood educators' enactment of particular languaging practices was more closely related to their agency and beliefs than to any official language policy of the program/classroom in which they worked. That is, even within the highly political nature of establishing and enforcing specific language policies, more often than not, teachers leveraged their ability to choose how they wished to language for/with children, modeling linguistic practices that they believed in over those they were told to enact and enforce. Our findings also suggest that policy-makers would benefit from consulting and/or including teachers in the policy-making process, since using their actual practice to inform policy may help formulate more effective and realistic policy.
Teachers' and children's dynamic languaging practices were documented across a variety of learning contexts (e.g., sociodramatic play, unstructured play periods) and instructional strategies (e.g., differing questions). Moreover, many benefits were associated with teachers and children drawing on their full linguistic repertoires, including effective meaning-making by drawing on one's complete knowledge and understanding Kim, 2016a;Kirsch, 2018b), legitimization of multilingual and multicultural identities (Gort & Sembiante, 2015;Kirsch, 2018a), creation of a non-threatening environment to develop language (Alamillo et al., 2017;Alanís, 2018;Kim 2016b;Kirsch, 2017), and enrichment of sociocultural spaces (Gort & Pontier, 2013;Gort & Sembiante, 2015;Kim, 2016b;Kirsch, 2017;Portolés & Martí, 2017). An important note, though, is that rarely were these languaging practices planned, or at the very least, they were not reported as such. This may suggest that when teachers language naturally in ECE contexts as they would outside of ECE contexts, they are supporting young EB children in myriad ways.
Although researchers have begun to examine dual language teachers' interpretation and implementation of bilingual pedagogies in K-12 contexts (CUNY-NYSIEB, 2020; Henderson & Palmer 2020), there is still a paucity of information on this topic in early childhood. The majority of the studies in this review mainly described translanguaging practices as "allowed" and "supported," leading us to wonder whether translanguaging in the ECE classroom has achieved its potential. Planning for strategic dynamic languaging--enacted by teachers and/or children--may enhance the existing documented benefits that bilingual children experience. Thus, we question what the consequences would be if early childhood teachers would do more than just allow translanguaging, and actually use it strategically.
There is evidence that teachers may need coaching with developing and implementing specific scaffolding strategies to better support multilingual learners in meaningful ways (de Sousa, 2017). However, the literature highlighted in this review represents only a slice of learning contexts and instructional strategies. Research that targets particular early childhood learning contexts and specific instructional strategies would enhance the field's understanding of both the expanding enactments of dynamic bilingualism but also its utility as practice and pedagogy.
To that end, teachers are already well-situated to draw on their agency to do this work as they are placed at the very heart of language policy-making, highlighting their purposeful and reflective choices of whether to adhere to the language program's (sometimes) rigid policies, and adapt these into learners' dynamic bilingual practices (Menken & García, 2010). A challenge here is that teachers often have little training directly related to language policy or planning and, subsequently, little formal preparation for meeting the needs of EB children's linguistic human rights (Wiley, 2008). Thus, greater teacher professional development related to policies may be helpful. However, a major takeaway is that policy makers should recognize teachers' languaging performances as largely unrelated to stated language policies. Instead, a better approach might be to focus on the tensions among teachers' lived experiences, language ideologies, expectations of young EB children, and teaching practices, and the subsequent results of those practices.
Because this review drew from qualitative literature, we did not focus on quantitative assessment or evaluation data related to the effectiveness of translanguaging as practice or pedagogy. Since children translanguaged in every study, our focus was then on how teachers positioned themselves and acted upon stated language policies, including how they worked within contexts of dynamic languaging. We recognize that the trend is to determine effectiveness through "academic" outcomes, but we sought to highlight the normalness of bilingual practices, which were effected regardless of context or language policies. Based on the studies included in this review, therefore, we cannot make quantitative claims of whether translanguaging was effective. That said, in addition to these qualitative studies, more experimental studies that explore the effectiveness of translanguaging in ECE contexts, including the relationship with literacy and the bilingualism of the surrounding community, would certainly be of interest to a large body of researchers and government officials. Included in this suggestion is the requirement that quantitative studies draw on different ideologies in creating coding schemes, conducting analyses, and presenting findings that do not reify existing monolingual norms.
Finally, existing resources for early childhood educators tend to operate from a "bilingualism as dual," or monolingual, perspective, not always intentionally leveraging the skills and experiences of young EB children and their families. In many of these instances, the ultimate goal is English, not bilingualism. For example, in drawing on existing literature, Head Start provides a comprehensive array of resources for ECE providers, but does so with a focus on one language at a time (e.g., "Resources demonstrate how to help DLLs develop their home language as they also move toward becoming proficient in English" [Retrieved from: https://eclkc.ohs.acf.hhs.gov/culture-language/article/planned-language-approach]). Similarly, Head Start's three recommended classroom language models for supporting young EB children in ECE contexts (i.e., dual language, home language as a base for English development, English with home language support) operate on the assumption that an adult in the ECE context can serve as a language model for monolingual English. However, often this is not the case (Pontier, forthcoming), and languaging practices to support young EBs as they expand their linguistic repertoires (while simultaneously developing socioemotional, physical, and other relevant and appropriate skills and experiences) are absent from available resources. Moreover, many of the ECE teachers who self-identify as monolingual in a language other than English often engage in bilingual languaging practices (Pontier, forthcoming). How these languaging practices fit into different models of early childhood bilingual education (which include specific language policies) has yet to be incorporated into available resources. We must also be critical and question whether the suggested models are an authentic fit for both the young EB children being served and the ECE teachers working with them.