What is a mother tongue?
By definition, a mother tongue is the language a child acquires in earliest childhood without formal instruction. Linguists regard the term “mother tongue” as imprecise, because it refers less to the person of the mother than to a speaker’s linguistic and cultural roots. For this reason experts often prefer the term “first language” or the English expression “native language”. What matters for a mother tongue is early and continual exposure to the language, which imprints its sounds and grammatical structure so deeply that the child uses the language automatically.
Mother tongue vs. first language:
The terms mother tongue and first language are synonymous – although the first language a child learns is not necessarily the language the mother speaks. The term mother tongue underlines that language acquisition in children begins already in the womb, while first language is more precise – it is the language a child learns first and intuitively. Children raised bilingually therefore acquire two first languages, provided they use both languages in everyday life and have a similar command of each.
How babies acquire language
Recognising and selecting sounds: Newborn babies can already perceive a large number of different phonemes (sounds characteristic of a language). Immediately after birth a baby begins to pick up the characteristics of its mother tongue by hearing its parents speak in various everyday situations. In doing so it filters out the most frequent sound patterns and learns to recognise particular speech rhythms.
“Sound inventory” and speech modulation: By six to nine months babies are familiar with all the characteristic sounds of their mother tongue. They can also detect changes in pitch and speech rhythm, for example when parents speak to them affectionately, angrily or during play. Although the baby does not yet understand the connection between words and the objects they refer to, it begins to imitate certain sounds and parts of words.
First words: At about one year a child begins to grasp the connection between words and objects or states. First words are often used broadly for several things (e.g. “ball” for anything that is round).
Object, verb, subject. Once a child perceives itself as a person and the world as composed of objects – roughly in the latter half of the second year of life – it begins to assign words correctly and to use verbs, sometimes already in two‑word sentences. Children at this age often refer to themselves by name to express a state: “Lisa hungry” or “Max ouch”.
Speaking and understanding: By three to four years of age a child knows all the basic structures of its mother tongue with regard to grammar, phonetics and speech rhythm. It can articulate long words and uses sentences with subject, predicate and object.
Theories of child language acquisition — does the mother tongue play a role?
Chomsky’s theory of universal grammar: A well‑known theory by the linguist Noam Chomsky holds that all languages spoken worldwide share common grammatical principles and that every human internalises these principles from birth. Thanks to this innate “universal grammar”, children do not need to learn all grammatical rules during language acquisition, but only the specific instantiations of their mother tongue.
Cultural theories as a basis for language acquisition: More recent research on language acquisition contradicts the assumption of innate grammatical structures as proposed by Chomsky. One argument for this is the finding that the part of the brain responsible for language acquisition is highly plastic in early childhood. Because children typically receive a large amount of very specific linguistic input from their environment in the first years, they develop an intuitive understanding of the grammatical structures and sound patterns of their mother tongue.
Parental support in learning to speak: The US psychologist Jerome Bruner developed the idea in the 1980s that the linguistic environment and parental interaction play a decisive role in children’s language acquisition. Building on Chomsky’s theory of universal grammar, Bruner proposed the concept of a parental Language Acquisition Support System (LASS).
