The goal of this theory is to explain the uniformity of language acquisition among humans despite ostensible differences in their native languages. Since Chomsky's original proposals in 1957, numerous elaborations and alternative theories have been proposed. Phonologists examine such phonetic shifts to construct theories about linguistic sounds in one language that can be used in comparing linguistic systems. The analysis of sounds in different languages can be very useful for foreign language teachers. Syntacticians describe how words combine into phrases and clauses and how these combine to form sentences.
Syntacticians describe the rules for converting the first sentence into the second.
The goal of semantic study is to explain how sequences of language are matched with their proper meanings and placed in certain environments by speakers of the language. Though grammatical, this sentence is largely meaningless in ordinary usage. The major divisions within the field of sociolinguistics are described below. In this respect, dialect should be distinguished from accent, which usually refers only to pronunciation. All speakers of a language speak a dialect of that language.