Table 1.

Topics Discussed in Research on Biliteracy.

Major issues the raised research in on biliteracy	Examples of studies	Summary of results
Cognitive skills and brain activity (neurolinguistic studies)	Bialystok (2001); Brice & Brice (2009); Cummins (2021); Del Maschio et al. (2020); Deluca et al. (2019); Ma et al. (2020); Marian & Kaushanskaya (2004); Pliatsikas et al. (2020); Ramírez-Esparza & García-Si- erra (2014); Soltero-González & Butvilofsky, (2016)	In comparison to poor bilingual writers, good bilingual writers held a broader and more complex view of their own writing process and showed more strategic knowledge, since they were more flexible in using both cognitive and metacognitive strategies and employed a wider range of more “elaborated” strategies.
Metalinguistic awareness	Basetti (2005, 2012); Bialystok (2001); D’Angelo, F. (2020); D’Angelo & Sorace (2022); Eviatar et al. (2018); Francis (1999); Kenner (2005); Oller et al. (2007); Robinson et al. (2022); Roehr-Brackin (2018); Tabors et al. (2003)	Biliterates differ from monoliterates in their ability to analyze and manipulate language units, and bilinguals who have developed an aspect of metalinguistic awareness through biliteracy can outperform native speakers in one or both of their languages, including a weak second language. Hence, there is a strong connection between metalinguistic awareness and biliteracy.
Phonological and phonemic awareness	Bassetti, (2005, 2012); Bialys-tok (2002, 2020); Cheung et al. (2011); Gottardo et al. (2011); Khalaf et al. (2019); Limberger et al. (2020); Medeiros et al. (2020); Pawlicka et al. (2018); Tabors et al (2003)	According to the Orthographic Depth Hypothesis, phonological transparency of an alphabetic writing system affects bilinguals’ reading and spelling, as biliterates rely more on grapheme-phoneme conversions for reading and phoneme-grapheme for spelling (i.e., learning to read in two similar writing systems is easier than learning to read in two different writing systems).
Relationship between reading and writing skills	Alkhaldi & Oshchepkova (2018); Bassetti (2012); Bi- alystok (2002); Cheung et al., (2011); Chung et al. (2019); Eviatar et al. (2018); Gottardo et al. (2011); Kenner (2005); Marian & Kaushanskaya (2004); O’Brien et al. (2019)	Bilinguals’ reading proficiency is a joint result of a language’s orthographic characteristics and instructional methods. Reading and writing involve the same processes in all languages, so good readers in one language tend to be good readers in another, as well as being able to spell in both languages. Some language structures and orthography determine the prerequisite skills that children acquire and the ease with which reading can be acquired. Biliterates tend to map a visual stimulus of one language onto an orthographic representation of both languages, and the lexical representation of non-target language is activated (eye-tracking data).
Parental strategies and SES of the families	Brito et al. (2021); Cobo- Lewis et al. (2002); Fernandes (2019); Goldenberg et al. (2011); Griva & Chostelidou (2014); Kenner (2005); Naeem et al. (2018); Nakamura (2018); Reese et al. (2006, 2008); Reese & Goldenberg (2008)	Home literacy practices predicted reading skills in bilingual children. Though the majority of parents were interested in their children’s bilingualism, families with low SES demonstrated a low level of involvement in promoting literacy.
Role of environment (neighborhood, community)	Claussenius-Kalman (2021); Hristo et al. (2017); Oller et al. (2007); Ramos et al. (2022); Reese & Goldenberg (2008); Reese et al. (2006); Tabors et al., (2003); Turdaliyevich (2022)	Bilingualism, when nurtured in well-designed environments of teaching and community, was beneficial for the maintenance of L1 and successful learning of L2. The community’s opinion about languages plays a fundamental role in establishing a child’s self-confidence about bilingualism as well as biliteracy.
Role of education	Barletta et al. (2011); Benson (2017); Carlisle & Beeman (2000); Cobo-Lewis et al. (2002); Elorza (2013); Gale et al. (1981); Goldenberg et al. (2011); Hinesly (2019); Ifont & Tovar-García (2018); Ken- ner (2005); Oller et al., (2007); Serna & Hudelson (1993); Uranova et al. (2022)	The type of bilingual program — immersion (target language only); maintenance (or developmental) bilingual instruction (L1 instruction continues after beginning substantial amounts of L2 instruction); dual-language (or two-way) programs (simultaneous bilingualism and biliteracy in both languages) — affects biliterate acquisition (it can be both positive and negative); school affects students’ confidence and self-identification; teachers’ beliefs about bilingual/biliteral students’ capacities to acquire a subject (there is a prevailing belief that a child’s native language is the cause of his/her learning problems).
L1–L2 transfer in writing	Barletta et al. (2011); Cenoz & Gorter (2011); Cummins (2021); Fitzgerald (2006); Genesee (2002); Kiramba, (2017); Lay (1982); Marian et al., (2021); Soltero-González & Butvilofsky (2016); Reese & Goldenberg (2008); Tabors et al. (2003)	Becoming literate in one’s L1 helps with literacy development in L2 and vice versa: writing well in one’s first language is associated with successful acquisition of writing skills in a second language (due to the process of language transfer).
Personal preferences and self- identification	Butvilofsky, (2016); Denissova et al. (2019); Kiramba (2017); Sabti et al. (2019); Soltero- González, Griva, & Chosteli- dou (2014)	Bilingual children with a low level of support and encouragement from schools and the community did not feel comfortable about their writing difficulties, among other things. Such children completed tasks unwillingly and did not achieve high scores in comparison to monolinguals.

Note. Languages presented in the studies: English, Spanish, Latin American Spanish, Catalan, Basque, Hakka, Mandarin, Cantonese, Náhuatl, French, German, Arabic, Russian, Gupapuyngu, Albanian, Armenian, Georgian