ABSTRACT
The grammar of any human language is composed of different systems: the lexicon, syntax, and semantics. Grammar is a system in the sense that it is a complex whole, made up of connected and interacting parts, a whole that is more than the sum of its parts. Syntax is a system made up of rules that determine how different categories of words can combine into phrases and then into clauses and sentences. Clauses and sentences are composed of a subject, which serves as a topic, a main verb, and any material that follows the verb. Discourse is the system that tells us how to use and understand language in specific contexts or situations of use. Grammar is language as a system that exists in the human head, whether or not it is being put to use. The lexicon, syntax, and semantics together make up grammar. Grammar constitutes a theory of what can be thought and said.
