To study language in an analytical and systematic way , linguists have categorised the subject matter of linguistics under the following heads : sound, grammar and meaning.
Sounds can always be studied from two different angles. Phonetic and phonological .Phonetics studies language at the level of sounds .The study focuses on how sounds are articulated by human speech mechanism and received by the auditory mechanism ,and how sounds can be distinguished and characterized by the manner in which they are produced. In other words phonetics is the study of the way human beings make ,transmit and receive speech sounds. It studies all possible sounds that human speech organs can make . It describes sounds without restricting its attention to any particular language.
Phonology studies the combination of sounds into organized units of speech ,the formation of syllables and larger units. It describes the sound system of a particular language and the combination and distribution of sounds ,which occur in that language . Classification is made on the basis of the phoneme, which is the minimal distinctive , sound segment eg,/m ,p, l/. The selection and organization of sounds in a particular language constitute the phonology of that language. Phonology studies only those contrasts in sound , which make differences of meaning with in a language.
Morphology and syntax are concerned with the grammar of language. Morphology studies the patterns of word formation by the combination of sounds into minimal , distinctive units of meaning called morphemes. A morpheme cannot be broken up because if it is broken up , it will not make sense. For example, the morpheme bat is made up of three sounds :/b/, /ae/,/t/.This combination makes up the single morpheme bat and if broken up it will no longer carry the meaning of bat. Words can be made up of a single morpheme such as bat or combinations of morphemes such as bats. Bats is made up of two morphemes bat and s. Morphology deals with the rules of combination of morphemes to form words. It studies the changes that take place in the structure of words .For instance , the morpheme take changes to took and taken; these changes signify changes in tense forms .
Syntax is the study of how words are arranged into higher units like phrases and sentences in “principled ways “.It deals with the rules and principles governing the arrangement of words into such higher linguistic units. Hence syntax is the grammar of sentences.
Semantics deals with the level of meaning in language . It tries to give an account of the meaning of both words and sentences. It also deals with how language is organized in order to be meaningful.