Languages evolve through natural selection, where the features that are most advantageous for communication are more likely to be passed on to future generations.

Language change can be divided into two main types: internal change, which is driven by the internal structure of the language, and external change, which is driven by factors outside the language, such as contact with other languages.

Convergence is the process by which languages become more similar to each other over time, typically due to contact between speakers of different languages.

Divergence is the process by which languages become more different from each other over time, typically due to the isolation of speakers of different languages.

Creolization is the process by which two languages merge into a single new language, typically due to the contact between speakers of different languages in a colonial or post-colonial context.

A loanword is a word or phrase that is borrowed from another language and incorporated into a new language.

Sound change is the process by which a language changes its pronunciation over time, typically due to changes in the way that words are articulated.

Semantic change is the process by which a language changes its meaning over time, typically due to changes in the way that words are used.

Syntactic change is the process by which a language changes its grammar over time, typically due to changes in the way that words are combined into sentences.

Morphological change is the process by which a language changes its word forms over time, typically due to changes in the way that words are inflected.

Historical linguistics is the study of language change over time.

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

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

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

Cognitive linguistics is the study of the relationship between language and thought.