Form of Language
Phonology is the sound system of a language and the rules that govern the sound combinations.
Morphology is the system that governs the structure of words and the construction of word forms.
Syntax is the system governing the order and combination of words to form sentences, and the relationships among the elements within a sentence.
Content of Language
Semantics is the system that governs the meanings of words and sentences.
Function of Language
Pragmatics is the system that combines the above language components in functional and socially appropriate communication.