Simultaneous Bilingualism

Simultaneous Bilingualism

Simultaneous bilingualism, also sometimes referred to as “native” bilingualism, refers to the type of bilingualism occurring when a speaker is exposed to two languages at or shortly after birth due to two languages being spoken in the home by the child’s primary caregivers (Kohnert et al., 2020). Each caregiver may speak a different language to the child, or bilingual caregivers may use both languages to speak to the child (Kohnert et al., 2020). The term simultaneous bilingualism “highlights the child’s concurrent experience with two different languages beginning at about the same time in his or her life, typically during infancy” (Kohnert et al., 2020, p. 89).

Dispelling a Common Misconception

Many believe that exposing a child to two languages concurrently in infancy or the first few years of life will result in initial delays in attaining early language milestones compared to single-language learning peers (Kohnert et al., 2020). However, research has found that simultaneous bilingual children achieve developmental language milestones, including first words, core vocabulary development, and combining vocabulary meaningfully, at the same rate as their monolingual peers when other factors, including environmental and sociolinguistic factors, are matched (Petitto et al., 2001; Petitto & Holowka, 2002). Simultaneous bilingual children use language for the same communicative purposes with the same level of clarity as monolingual children (Kohnert et al., 2020, p. 89). Additionally,  the number of words used by bilingual children from middle-income families is consistent with the number used by monolingual children from middle-income families when comparing the inventory in both languages to one language (Marchman & Martínez-Sussman, 2002; Pearson et al., 1993).

Language Characteristics in Simultaneous Bilingual Children

Challenges in Describing Simultaneous Bilingual Language Characteristics

Providing a comprehensive description of  bilingual language acquisition and typical language characteristics for simultaneous and sequential bilingual children is challenging due to the following: 

• The paucity of research focusing on typical bilingual language acquisition paired with the heterogeneity of bilingual individuals and the unique factors influencing their language development makes it difficult for researchers to reach a consensus regarding the bilingual experience.

• Most of the available research does not differentiate between sequential and simultaneous bilinguals. 

• Of the research that has been conducted, many studies focus on specific language groups. The results of these studies may not directly apply to other bilingual populations. For example, Spanish/English bilingual studies may display different results than Chinese/English-focused or Russian/English-focused studies.

• Research often does not differentiate between bilingual individuals in additive bilingual situations versus those in subtractive bilingual situations. Research examining bilingual or multilingual language acquisition of multiple Romance languages (i.e., Spanish, Italian, French) conducted in Europe, where multilingual skills are more culturally valued, may display different results than studies on children of immigrant populations in the U.S. in which the mainstream population values L2 (English) more than L1.

Please refer to the Sequential (Successive) Bilingualism page in addition to this page for a more comprehensive picture of bilingual language characteristics. Note that some information is included on both pages. This inclusion is partly due to the overlap in the features of bilingual development for simultaneous and sequential bilingual children. The inclusion of the same information on each page is also an outcome of the research on bilingualism. Many research studies do not or are unable to differentiate between simultaneous and sequential bilingual participants. Consequently, most research on bilingual children is relevant to general bilingual populations as opposed to either sequential or simultaneous bilinguals. 

The following sections summarize the research findings on aspects of simultaneous (and generalized) bilingual language. 

Vocabulary & Lexical Development 

Heterogenous Vocabulary Acquisition in Bilinguals 

Vocabulary acquisition in bilingual children is highly variable, given individual circumstances. Patterson and Pearson (2022) give the following factors which contribute to the variability of vocabulary acquisition in bilingual children:

• Language input amounts

• Language input contexts in which input is experienced in each language (i.e., home, school, community environments)

• Level of proficiency at the time input occurs

• Timing of initial exposure

• Proportion of exposure (i.e., estimated percentages of time exposed to L1 or L2)

• Loss of L1 as L2 is introduced and developed (i.e., subtractive bilingualism)

Measures of Vocabulary in Bilinguals 

Two standard measures of bilingual vocabulary include total vocabulary and conceptual vocabulary. Total vocabulary represents the number of words the child knows across their two languages (Core et al., 2013). Conceptual vocabulary measures the number of words a child knows representing unique concepts across the two languages (Core et al., 2013). For example, if a bilingual child knows both the words agua and water, they would get credit for knowing two words in a measure of total vocabulary. However, this would only count for one word in a measure of conceptual vocabulary since agua and water represent the same concept. These translation equivalents are called doublets, whereas singlets are words known in only one language (Pearson et al., 1993). 

Study on Vocabulary in Support of Simultaneous Bilingualism 

Junker and Stockman (2002) examined vocabulary skills in bilingual toddlers between 24 and 27 months to examine whether bilingual children are at a language-learning disadvantage. Their study also investigated if bilingual children use a unitary language system in which features from both languages are represented. After reviewing the toddlers’ vocabularies, findings revealed that bilingual toddlers were not inferior in conceptual vocabulary size and verb diversity when words in both languages were combined. The authors found that nearly half of the bilingual conceptual vocabulary (43%) was associated with lexical forms in both languages. This finding suggests that language separation is possible at two years of age. The study’s findings contribute to growing research that early simultaneous acquisition of more than one language is not an inherent disadvantage for the child (Junker & Stockman, 2002). 

Research Findings on Bilingual Vocabulary Development

• Children attach meaning to a referent and word form to develop vocabulary (Miller & Gildea, 1987). An initial step in this process is creating a phonological representation of the word (i.e., a representation based on the speech sounds of the word) (Locke, 1983). Phonological memory skills, abilities “to store novel sound sequences,” are related to vocabulary development (Hoff & McKay, 2005, p. 1041). Hoff and McKay (2005) found bilingual toddlers performed similarly to monolingual peers in the repetition of nonsense words, suggesting comparable phonological memory skills between monolingual and bilingual children, which are shown to relate.

• Studies have examined bilingual children’s use of mutual exclusivity (Davidson et al., 1997; Davidson & Tell, 2005; Frank & Poulin-Dubois, 2002). Studies have found that children, at least monolinguals, often assume that an object has only one label, calling this phenomenon the mutual exclusivity constraint (Markman & Wachtel, 1988). Typically, children exclude objects that already have a name when assigning the meaning of a novel word (Markman & Wachtel, 1988). Davidson and colleagues (1997) investigated the extent to which bilingual children would preserve mutual exclusivity within a language (i.e., accept two names for an object when the two names were from the same language). Their study design was based on research indicating bilingual children were more likely to accept two names for an object when it was apparent that each name was from a different language (Au & Glusman, 1990). Results showed that while bilingual children in the study did apply the mutual exclusivity constraint, they did not use it as frequently as the age-matched monolingual participants (Davidson et al., 1997). 

• Pearson and colleagues (1995) found a lack of preference for learning L2 words corresponding to words already known in L1. This lack of preference suggests it is not necessarily the case that knowing a word in one language will make it easier to learn the word in a second language.

• Thordardottir (2019) found that amount of language exposure is a better predictor of receptive and expressive vocabulary in bilingual children than the age of exposure. The author argues that the results of this study “call into question the traditional separation between simultaneous and sequential bilinguals and show that an early start of bilingualism does not in and of itself predict better performance or performance within the monolingual range” (Thordardottir, 2019, p. 236). 

Additional Research Findings on Simultaneous Bilingual Vocabulary 

• Simultaneous bilingual language learners acquire first words at the same rate as monolingual children (Patterson & Pearson, 2022). 

• Simultaneous bilingual language learners have similar rates of acquisition (Pearson et al., 1993) and distribution of vocabulary (Nicoladis, 2001) as their monolingual peers. 

• Research suggests that simultaneous bilinguals develop separate lexical systems for each language starting around 18 months of age (DeAnda et al., 2016).

• Simultaneous bilinguals’ lexicons are affected by the amount of time exposed to each language (Patterson & Pearson, 2022). 

Phonetics & Phonology 

Acquisition of bilingual phonology requires mastery of “the phonological knowledge base and the production system requirements for phonemes and syllable and word shapes in both languages” (Gildersleeve-Neumann et al., 2008). Children need to understand the phonemic inventories, phonetic production, and phonotactic constraints of each language.  

Phonotactic constraints are rules that determine how a syllable can be structured in a language (Nordquist, 2020). For example, a word never begins with /tl/ in English. Additionally, English phonotactics allow the combination of four consonant phonemes used consecutively as in the word “twelfths,” (phonetically represented as /twɛlfθs/). In Spanish, however, only three consecutive consonant phonemes are allowed, and only between syllables, as in “estrella” (star) represented phonetically as /estɾeja/. 

Understanding phonemic inventories includes knowing the speech sounds, also called phones (LinguisticsStudyGuide.com, 2019), that carry meaning in a language, known as phonemes (Britannica, 2009). In English, /l/ and /ɹ/ are independent phonemes, demonstrated by ‘row’ and ‘low’ having distinct meanings. In contrast, the distinction between /l/ and /ɹ/ is not meaningful in Japanese (IMABI, n.d.). In Japanese, /l/ and /r/ are allophones (IMABI, n.d.). Allophones are sounds that, although acoustically distinct, do not alter the meaning of sound in a given language (Britannica, 2018). The /l/ and /r/ phones are used interchangeably in many Asian languages and do not alter the word's meaning. This article provides greater detail on the differences between phonemes, allophones, and phones (LinguisticsStudyGuide.com, 2019). 

Research Findings on Bilingual Phonetics & Phonology

• Cross-linguistic transfer may affect bilingual speakers' phonetic productions in situations when one language’s phonetic inventory is applied to the other language (Gildersleeve-Neumann et al.,  2008). For example, a bilingual Spanish-English speaking child (whose L1 is Spanish) may use Spanish vowels in English words (e.g., [moŋ.ki] instead of /mʌŋ.ki/) or use an alveolar trill /r/, also called the rolled ‘r’, as in “perro”,  in the English word “run.”

• In a study on English speech sound development in bilingual Spanish-English preschoolers, Gildersleeve-Neumann and colleagues (2008) found that bilingual children with relatively balanced exposure to both languages showed higher error rates in speech sound production than those who had greater exposure to English. However, error rates decreased over time at the same rate for all participants in the study, and these results were consistent with expected developmental changes in that age range. Based on the decrease in error rates over time, the authors asserted that future results for these bilingual children would likely be adult-level competency in both languages (Gildersleeve-Neumann et al.,  2008).

• Studies examining speech-sound development in Spanish-English bilingual children indicate that Spanish-English bilingual children’s speech production is most accurate on phonemes shared between their two languages (Goldstein et al., 2001; Fabiano Smith & Goldstein, 2010; Montanari et al., 2018). However, these shared phonemes could be common, early-developing phonemes that are present in most languages. 

• Gildersleeve-Neumann and Goldstein (2022) summarized research findings by asserting that bilingual children make similar developmental speech error types as monolingual peers. However, the frequency of these errors may be higher in bilingual children than in monolinguals up to around age five (Gildersleeve-Neumann & Goldstein, 2022). 

Morphosyntax

Research Findings on Bilingual Morphosyntax

• Thordardottir (2014) summarized the findings from 4 studies they conducted with simultaneous French-English bilinguals from 2011 to 2014 to explore the effects of relative language exposure on language knowledge and processing. The study found that the amount of language exposure to each language had a significant impact on the rate of grammar acquisition in that language. Additionally, it was found that the development of grammar followed language-specific patterns of the order of acquisition and accuracy and error types (Thordardottir, 2014). In a subsequent study, Thordardottir (2015) measured mean length of utterance (MLU) and accuracy and diversity of morpheme use in simultaneous French-English bilingual preschoolers and compared their scores to monolingual peers. The study’s results reinforced their previous findings that “grammatical development in each language was strongly influenced by amount of same-language experience” (p. 97). Bilingual participants with relatively equal exposure in both their languages showed similar shows to monolingual participants in both languages, and children with unequal exposure showed unequal scores (Thordardottir, 2015). 

• Based on a review of literature, Genesee and Nicoladis asserted in 2007 that simultaneous bilingual children generally “exhibit the same rate of morphosyntactic development as monolingual children, at least in their dominant language” (p. 326). However, the authors also acknowledge there is evidence of cross-linguistic transfer of some morphological and syntactic features that differ between the two languages (Genesee & Nicoladis, 2007). 

• Marchman and colleagues (2004) examined the correlation of lexical and grammatical acquisition in simultaneous bilingual Spanish-English speaking children. They examined vocabulary and grammar in both languages of 113 simultaneous Spanish-English toddlers aged 17-30 months. The study found that grammar skills were strongly tied to vocabulary growth in the same language, which suggests strong within-language lexical-grammatical associations. Results also indicated that grammar skills were only weakly related to vocabulary and grammar development in the other language, suggesting a less significant relationship between cross-language associations. The study's results support solid lexical-grammatical continuity in the early acquisition of a given language (Marchman et al., 2004).

• Schulz and Grimm (2018) conducted a longitudinal study comparing the acquisition of morphosyntactic and semantic phenomena in simultaneous and sequential bilingual children to monolingual children. The monolingual participants in this study spoke German, the simultaneous bilinguals spoke German and another language which varied, and the sequential bilinguals all spoke German as their L2 with L1 varying. They measured six different morphosyntactic and semantic phenomena in German that existing literature has shown to be typically acquired in L1 in early, late, or very late stages (3 to 6 years of age). The simultaneous bilingual children in the study showed an advantage over their sequential bilingual peers in early acquired features, which leveled out over time, while there was no difference in late acquired features. Additionally, the simultaneous bilingual participants acquired early features similarly to monolingual peers but showed some delay in late features, although the amount of delay decreased over time. The authors conclude that “age of onset effects are modulated by effects of timing in monolingual acquisition…contrary to expectation, input in terms of language dominance, measured as the dominant language used at home, did not affect simultaneous bilingual children’s performance in any of the phenomena” (Schulz & Grimm, 2018, p. 2732). 

Narratives

Research Findings on Bilingual Narratives

• Gutierrez-Clellen (2002) conducted a study in which story recall and story comprehension tasks were measured in Spanish-English bilingual children. Children in this study demonstrated greater narrative recall and story comprehension in English. The authors also found that bilingual children may perform less satisfactorily on narrative recall tasks than spontaneous narrative production tasks for one language. These results suggest that narrative assessment tasks in L1 and L2, which appear comparable, may not actually pose the same processing demands on a bilingual speaker (Gutierrez-Clellen, 2002). 

• Uccelli and Paez (2007) conducted a study examining narrative and vocabulary skills in bilingual Spanish-English speaking kindergarteners and first-graders. They found kindergarten Spanish story structure predicted first-grade English narrative quality, and Spanish narrative quality was best predicted by kindergarten Spanish vocabulary. This study suggests a relationship between reading skills, narratives, and vocabulary and emphasizes the importance of encouraging vocabulary and narrative development in L1 for bilingual children entering educational settings.

• Research has shown that different narrative elements are valued in different cultures (McCabe & Rollins, 1994). McCabe and Rollins (1994) found that children from various cultures emphasized different narrative elements during elicited narrative tasks. Latino children in the study emphasized family connections and relationships rather than focusing on sequential events. Additionally, Japanese children in their study produced narratives that consisted of concise, haiku-like conveyance of experiences with little attention paid to the narration of the event’s details. These differences exemplify how the production of narratives can differ significantly in structure, which may present a challenge to an SLP who evaluates the child to determine the presence of a language disorder or difference. This study emphasizes the importance of making distinctions between cultural differences in narrative structure and the presence of a language disorder.

Literacy

Research Findings on Bilingual Literacy

• Both monolingual and bilingual children use their knowledge of how words are pronounced when decoding unfamiliar words they have not read before (Gutierrez-Clellen, 1999). This knowledge can be orthographic (based on the memory of other words with similar letter sequences) and phonological (familiarity with listening and producing sequences of sounds) (Gutierrez-Clellen, 1999).

• Languages can have transparent or opaque orthography, all known as deep or shallow orthography (Goswami et al., 1997; Gutierrez-Clellen, 1999). Spanish is a language with high orthographic transparency because it has consistent sound representations in written words (i.e., Spanish is written the way it sounds and vice versa) (Goswami et al., 1997; Gutierrez-Clellen, 1999). In contrast, English represents a language with opaque orthography since there is extensive variation in the way words are written and pronounced (Gutierrez-Clellen, 1999). Goswami and colleagues (1997) found that when bilingual children are asked to decode nonsense words, children from L1 languages with high orthographic transparency may demonstrate greater decoding accuracy with transparent orthographies than children reading languages with opaque orthographies. These findings indicate that increasing target word familiarity with English (opaque orthographic) words and ensuring that bilingual children have multiple strategies for decoding and spelling new words are important for literacy development in English. Strategies for decoding novel words could include increased reading experiences, increased phonological knowledge and awareness, and explicit instruction in the structures of L1 and L2 (Goswami et al., 1997).

• To spell unfamiliar words, children typically use strategies including memory, analogy, and invention (Ehri, 1997),  which all involve phonological and orthographic awareness. Bilingual children learning English may have a limited “restricted store of memorized representations for English words, as well as limited phonological knowledge about the pronunciations of different words, that can then help them generate or generalize to unfamiliar words” (Gutierrez-Clellen, 1999, p. 286). For these children, learning how to read and spell in their second language involves formulating new phonological representations and acquiring orthographic rules that are language-specific (Gutierrez-Clellen, 1999).

• Wong and Underwood found evidence that children learning English as a second language may rely on the context within text more often than typical monolingual readers to read words they have difficulty processing (1996), similarly to monolingual English readers with less proficient reading skills (Nicholson et al., 1991).

• Jimenez, Garcia, and Pearson (1996) identified strategies used by bilingual sixth and seventh graders who were skilled English readers. These strategies identified in their study included searching for cognates (i.e., words that are related across languages like “president” in English and “presidente” in Spanish), full or partial internal translating of text from one language to another, resolving unfamiliar vocabulary using context and prior knowledge, monitoring comprehension, and asking questions while reading. These strategies involved metacognitive processes that incorporated reviewing, evaluating, monitoring, and questioning text (Jimenez et al., 1996).

Original Contributor: Jerae Bjelland, Winter 2009

Updated June 2022