Bilingual First Language Acquisition in Young Children

Introduction and the Bilingual Paradox

It is common knowledge that all over the globe young children seem to effortlessly acquire two or more languages at one time. Yet some uphold the belief that children who are exposed to multiple languages too early may experience developmental language delays and/or confusion — the dividing line as to what constitutes "too early" remaining a gray area. Scientific research has attempted to examine whether young bilinguals can ascertain that they are acquiring two separate and distinct languages early on (Watson, 1996). This paper examines the criteria for measuring early language development, the concepts associated with gauging a child's developmental progress, the research supporting the prevailing theories, and the significant findings inherent in credible research in these areas.

The line of thought that most closely resembles popular opinion about whether or not children should be raised bilingual from birth is called the Bilingual Paradox. It is a paradox because there are conflicting contemporary theories about whether or not simultaneous bilingual exposure is the preferred method of introducing two languages. While much research shows that children exposed to two languages simultaneously between the ages of zero and three achieve major milestones within the same timeframe and with similar results as monolinguals, the prevailing popular view has been to teach a child one language early on and reserve the introduction of a second language for the later school years. The thinking behind this latter position is that introducing two languages early on will confuse the child, or that the child will be disadvantaged in mastering one or both languages. There are, however, steps parents can take early on — grounded in proven research — to give their child an advantage in learning language skills. Methodologies, tools, timing mechanisms, and support strategies have been developed through testing and observation that aid children in successful and timely language development, specifically in the adoption of multiple languages.

Competing Theoretical Frameworks

Bilingual Deficit Hypothesis

One of the theories regarding bilingualism and its potentially detrimental effects on children's language development is called the Bilingual Deficit Hypothesis. According to this theory, being exposed to and learning two languages equally during language development requires more effort and causes more stress for children. Because of this, there is concern that bilingualism delays children's initial production of the precursors to speech. One notion associated with this concept is the "babbling drift" hypothesis, which holds that when children begin to babble in their first two years of life, their sounds resemble the phonemes of their caregivers' language duality without regard for substance. While some researchers have found predictable phonemic differences among babies of caregivers with different language backgrounds, others have found no evidence of acoustic differentiation among such babies (Oller et al., p. 408).

The Bilingual Deficit Hypothesis conveys the notion that children who are simultaneously exposed to two or more languages early on suffer language delays and confusion. The theory further assumes that these children suffer a disadvantage in lacking the same mastery over one language as a monolingual child. Concerns center on "language mixing" and a lack of appropriate usage and development of syntax for each language. The Unitary Language System Hypothesis details a specific assumption about how early bilingual representation can cause developmental delay.

Unitary Language System Hypothesis

The Unitary Language System Hypothesis holds that, until the age of three, a child exposed to two languages has a single fused linguistic representation. This implies that a language delay is inherent in the need to sort out the two languages once the child is able to differentiate between them. The genesis of this line of thought was a study conducted in 1978 by Volterra and Taeschner. The study examined bilinguals in the one-word stage (approximately one year old) and noted that there were few semantically corresponding words across the two languages. The classic example is: if a child uses the word "ball" in one language, he or she will not use the equivalent of "ball" in the second language to express the same idea — implying that the children are not drawing on both languages for the same concepts at the same time (Caputi, 1986).

Essentially, the theory states that if the child already has a verbal concept in one language, they will not be motivated to express it using a second language until they begin to recognize that they are using two distinct languages. Volterra and Taeschner cite the example of one child who insisted that a hairpin was not a molletta (Italian) but a klammer (German). In their observations of three children, they reported that the children almost entirely lacked doublets — two words representing a single object or concept — until a seven-month period had elapsed. This contradicts Petitto's conclusion that the capacity to differentiate between two languages is established prior to first words. Volterra stated that once the seven-month period had passed, the children began using translation equivalents (also known as doublets) in 30% to over 90% of all words. Since Volterra studied one-year-olds, the indication is that the children were well past the age of one when the production of translation equivalents matured (Dromi, 1987). The contradiction with Petitto's findings appears to be primarily one of timing, given that the average monolingual child produces a first word at approximately one year of age.

Clark's Principle of Contrast (1987) supports Volterra's concepts and asserts that young bilinguals "reject cross-language synonyms in their earliest lexicons." Clark claims that during the first stage of vocabulary development, the child assumes each word has a separate and distinct meaning. Clark's theory further states that the child will tend to accept the word from the language they grasp most quickly, or at least until their vocabulary reaches 150 words. Parents can be mindful from the outset of their own patterns of language usage and whether they tend to naturally favor one form of language expression over the other, since a child is highly susceptible to the parent's linguistic influence.

Bilingual Advantage Hypothesis

The other prevailing theory, the Bilingual Advantage Hypothesis, holds that children raised in a bilingual environment have higher intellectual flexibility due to richer language input and therefore have an easier time producing speech sounds (Oller et al., p. 409). Evidence to varying degrees exists to support both theories.

According to the research of Kimbrough Oller, some of the fears about the detrimental effects of early bilingual exposure may be allayed (Oller, 1997). In Oller's observations of English- and Spanish-speaking children, he found that bilinguals were no less intelligible than monolingual children and in some cases were more intelligible. He further states that by the time bilinguals reach school age, they have a larger conceptual space and their vocabularies are at least as large as — if not more diverse than — those of monolinguals, giving them an advantage both socially and in communicating with a larger population.

Differentiated Language System Hypothesis

The Differentiated Language System Hypothesis challenges the unitary view. In this framework, language mixing occurs according to regular grammatical patterns and mirrors sociolinguistic factors — that is, the child's surroundings and tendency to mirror the language emphasis of their parents or primary caregivers. The crux of this premise is that language mixing is not the result of biological overload, confusion, or inability, but rather a demonstration that children are exhibiting distinct syntactical nuances at an early age. Evidence suggests that children mirror the emphasis of their primary caregiver, whether that be a parent, grandparent, childcare worker, or sibling.

Earlier empirical data on the two prevailing hypotheses were premised on studies beginning at eighteen months, focusing on multi-word combinations. By the age of eighteen months, early language milestones such as first word, first fifty words, and first two-word combinations have already occurred. More recent studies have examined these hypotheses from the perspective of infants and very young children.