105 Heritage Language Journal, 12(2) August, 2015 Book Review Heritage Language Teaching: Research and Practice. (2014). Sara Beaudrie, Cynthia Ducar, and Kim Potowski. Columbus, OH: McGraw-Hill Education. 241 pp. Reviewed by Ellen J. Serafini, George Mason University Heritage Language Teaching: Research and Practice valuably contributes to the field of heritage language learning and pedagogy by offering readers a coherent vision for curricular design, instruction, assessment, and administration in heritage language (HL) courses and programs. Despite a growing interest in promoting, maintaining, and teaching HLs in the United States, the authors argue that few educators who teach specialized HL courses or mixed courses with both HL and second language (L2) learners have actually been exposed to or received formal training in sociolinguistic concepts, which limits their ability to effectively meet learners' linguistic and affective needs in the classroom. To address this lack of training, the book advocates for an approach grounded in sociolinguistic principles and fills a key gap in HL education by providing an accessible resource for practitioners with varying levels of knowledge in this area. Chapter 1 begins with an overview of useful statistics about HL education and linguistic diversity in the U.S. and introduces the reader to the linguistic, affective, cultural, and academic differences that distinguish HL learners from native or 'homeland' speakers and their second language (L2) peers. Such differences underscore the need to offer specialized courses tailored to meet heritage learners' instructional needs, an endeavor made more complex by the fact that HL learners are a highly heterogeneous group themselves with varying linguistic and cultural backgrounds. Chapter 1 closes by proposing a set of teacher competencies built around fundamental sociolinguistic considerations, such as knowledge of social and linguistic processes underlying bilingualism and languages in contact. Chapter 2 further fleshes out core sociolinguistic concepts that HL teachers should understand, including the differences between "languages" and "dialects," the notion of speech register, natural features of languages in contact, "standard" language ideologies, and patterns of intergenerational language shift to English. For example, teachers must recognize that while all dialects are rule-governed and equally valid linguistically, some geographic and social varieties are accorded more power and prestige than others and the varieties HL learners speak tend to be socially stigmatized for being "associated with marginalized social/ethnic groups" (p. 15) and exhibiting features of linguistic contact (e.g., code-switching). Instead of negatively reacting to the use of "Y" because "X" is more 'correct', HL educators should understand the many functions that code-switching serves in bilingual communication and should capitalize on students' bilingual resources in the classroom, one example being to allow students to write the first draft of an essay in code-switched language and later revise (Nichols & Colon, 2000). To illustrate the notion of speech register, the authors adopt an analogy from Zentella (1997) that compares clothing that is expected at the beach versus at a wedding with the type of language that is expected in informal contexts (e.g., home) versus in more formal ones (e.g., school). In the authors’ view, HL teachers are responsible for raising students' awareness of which type of language is appropriate in which context(s) and the "communicative consequences" (p. 17) of their choices, such as negative reactions to the use of informal language in formal contexts (e.g., using cuz versus because in a class essay).