How do children acquire two languages simultaneously?

The question to how child acquire two languages simultaneously is supported by two different hypotheses. The different hypotheses are:

1. Dual Language System Hypothesis

2. Unitary Language System Hypothesis

Does Age Matter?


There are many different types of Bilingualism that have been discussed. The different types include Infant Bilingualism, Childhood Bilingualism and Adolescent/Adult Bilingualism. Infant Bilingualism usually refers to the simultaneous learning of two different languages (Taylor 1970, p.6). An example of this could be when a baby is born into a family where the mother and father speak different languages and speak both of the languages to their child. Childhood Bilingualism is when a child learns one language before the other (Taylor, p.6). They usually do not acquire their second language until the early school years. An example of this could be when a child is raised speaking a different language then the language that is spoken in their school. In the United States, many children who enter school without the capability to speak english will attend an English as a Second Language Program (ESL). Adolescent and Adult Bilingualism is when a child acquires their first language and speaks it for most of their life and learn a second language later on in their life (Taylor 1970, p.6). They usually will become familiar with the content of the new language, but usually have difficulty acquiring the formal system of the language.

Due to this it has been claimed that as an individual gets older it is more difficult to learn a new language. This is due to the fact that the language centers in the brain begin to harden, as an individual grows older. In a study done by Dimitrijevie, it was discovered that the earlier a child is introduced to a foreign language the better their pronunciation will be (Taylor 1970, p.6). Along with this, a study done by Carrol showed that there was in fact a negative correlation in the success of learning a new language and the individual’s age (Taylor 1970, p.6).

Along with this, it is more difficult for an adult/adolescent to learn a new language as well as a younger child because they are no longer in the critical period for language learning (Williamson 2009). In Critical Period for Language Development, it was stated that the Critical Period lasts from birth to late childhood, or in some cases puberty. As time goes on, the speech and language centers of the brain become localized to the left hemisphere (Williamson 2009). This supports the idea that the ability to learn a new language is no longer available because the neural substrate is no longer available once an individual escapes the critical period.