8.4. Language Development

Given the complexity of language, it seems remarkable that young children master it very quickly and with relative ease. We are apparently born with a biological predisposition to acquire language (Chomsky, 1965; Fernández & Cairns, 2011). Language develops in the absence of formal instruction and appears to follow a very similar pattern in children across the world. However, early language exposure is important for proficient language development (Johnson & Newport, 1989; Lenneberg, 1967; Singleton, 1995). It becomes more difficult to learn new languages (especially grammar and pronunciation) as we get older, however, people often have to do so, especially when immigrating to a new country (Hakuta et al., 2003).

Language development begins very early on in life (see Table 8.1). The fetus can hear muffled voices from the outside world, and so learns about language even before birth. Their mother’s voice is the loudest and most consistent voice they hear during the fetal period, which explains why newborn babies can identify their mother’s voice and her native language (DeCasper & Fifer, 1980; Moon et al., 1993).

Table 8.1. Stages of Language and Communication Development

You may recall that each language has its own set of phonemes (or speech sounds). At birth, all babies can differentiate between phonemes from all human languages, even if they are not being used in their environments. At about 7 months, babies start to produce speech sounds – a process known as babbling. Babies exposed to sign language also babble with hand gestures (Petitto et al., 2004). Babies are just as likely to babble when they are alone as when they are with their caregivers (Fernández & Cairns, 2011), but they also have periods of social babbling, where they look to others to respond to their babble (Laing & Bergelson, 2020). By about 11-12 months, babbling becomes more speech-like, and contains more phonemes from the language(s) that babies are hearing around them (Laing & Bergelson, 2020). Around the same time, babies lose their ability to hear the difference between sounds that do not occur in their speech environments (Jensen, 2011; Werker & Lalonde, 1988; Werker & Tees, 1984). For example, in Hindi, there are two “t” sounds that are easy for people who speak Hindi to differentiate between, but often sound the same to English speakers. Similarly, the phonemes associated with the letters  r and l in English, often sound the same to Japanese speakers.

Generally, a child utters their first word between the ages of 1 year to 18 months. For the next few months, a child will learn a lot of new words, but will only produce one-word utterances. A child’s early vocabulary is limited to familiar objects or events, often nouns. These words often carry larger meaning (Fernández & Cairns, 2011), for example, a child saying “cookie” could be identifying a cookie or asking for a cookie.

As a child’s lexicon grows, they begin to use simple sentences and acquire new vocabulary at a very rapid pace. In addition, children begin to demonstrate a clear understanding of the specific rules that apply to their language(s). During this time, children frequently overgeneralize grammatical rules. For example, in English, the letter “s” is often added to the end of a noun to make it plural, e.g., one dog versus two dogs. Young children might also say “two gooses” or “three mouses.” Clearly, they understand the rules of the language but have not yet learned all the irregular exceptions (Moskowitz, 1978).