Universal Grammar Theory

Babies don't comprehend the words that are being said to them, but they do possess an innate ability to understand the sound of the human voice and to discriminate between parts of language. Experiments done on babies as young as a few days old have shown they recognize phonemes, which are the smallest units of speech that differentiate one word from another.

The idea that explains this is known as Universal Grammar Theory and states that all children are born with an innate ability to acquire, develop, and understand language. If we look at grammar as the laws of language, we could say that all humans are born with an understanding of these laws. While different languages may have different kinds of grammar, humans have a natural predilection to learn and use them.

The realization that very young children innately understand aspects of language has shattered the long-held belief that the mind starts as a blank slate. Behavioral psychologists had assumed that grammar and language were learned solely by listening to it being spoken. Now, the common belief is that language has an inherent genetic component. The human brain is hardwired to develop grammatical language, even without being exposed to it as a baby.

The man credited with this revolution is MIT linguistics professor Noam Chomsky. Chomsky developed the theory in the 1950s and 60s before there was scientific equipment, such as the MRI, to show brain activity. Chomsky believed grammar must be a universal constant in humans because of something he dubbed the poverty of stimulus. This aspect of universal grammar argues that it is not possible that children are exposed to enough of their native language to learn it in a purely behavioral context. Keep in mind that this doesn't mean exposure to one's native language isn't necessary, just that it can't account for the entirety of learning a language.

Chomsky argued that the human brain contains a limited set of constraints for organizing language. This implies in turn that all languages have a common structural basis: the set of rules known as "universal grammar".

Universal grammar is the theoretical or hypothetical system of categories, operations, and principles shared by all human languages and considered to be innate. Since the 1980s, the term has often been capitalized. Also known as Universal Grammar Theory.

The concept of a universal grammar (UG) has been traced to the observation of Roger Bacon, a 13th-century Franciscan friar and philosopher that all languages are built upon common grammar. The expression was popularized in the 1950s and 1960s by Noam Chomsky and other linguists.

The Universal Grammar Hypothesis – the idea that human languages, as superficially diverse as they are, share some fundamental similarities, and that these are attributable to innate principles unique to language: there is only one human language (Chomsky 1995: 131)

Universal grammar is usually defined as the:

 “System of categories, mechanisms and constraints shared by all human languages and considered to be innate.”

(All) human languages share certain properties.

EASE AND SPEED OF CHILD LANGUAGE ACQUISITION: Children learn language quickly and effortlessly, on minimal exposure.  UNIFORMITY: All children acquiring language go through the same stages in the same order.

Arguments (1)-(4) are generally regarded as the most powerful ones;

Ease and speed of child language acquisition. It has been often suggested that children acquire grammatical systems of enormous complexity rapidly and effortlessly on the basis of very little evidence, and by “mere exposure”, that is to say, without explicit teaching (Chomsky 1962: 529, 1976: 286, 1999, Guasti 2002: 3). In fact, they get vast amounts of language experience. If we assume that language acquisition begins at age 1 and ends at age 5 and that children are exposed to language for 8 hours a day, they get 11680 hours of exposure (4x365x8 = 11680). At 3600 input words per hour (the average number of words heard by the children in the Manchester corpus), 2 this amounts to over 42 million words over four years.

Uniformity Some researchers (e.g. Stromswold 2000, Guasti 2002) have suggested that children acquire language in a very similar manner, going through the same stages at approximately the same ages, in spite of the fact that they are exposed to different input.