The lexicon is the mental representation of a word, including its meaning, pronunciation, and spelling.

Syntax is the set of rules that govern how words are combined into sentences.

Semantics is the study of the meaning of words and sentences.

Pragmatics is the study of how language is used in social interaction.

First language acquisition is the study of how children acquire their first language.

Second language acquisition is the study of how people learn a second language.

Bilingualism is the ability to use two or more languages.

Multilingualism is the ability to use three or more languages.

Psycholinguistics is the study of the relationship between language and thought.

Neurolinguistics is the study of the relationship between language and the brain.

Sociolinguistics is the study of the relationship between language and society.

Anthropological linguistics is the study of the relationship between language and culture.

Gender and language is the study of the relationship between language and gender.

Critical discourse analysis is the study of the relationship between language and power.

Ideological discourse analysis is the study of the relationship between language and ideology.