Language variation is influenced by a combination of geographical isolation, social stratification, and historical events. Geographical isolation can lead to the development of distinct dialects, social stratification can result in different language varieties used by different social groups, and historical events can shape language change and variation.

A dialect is a regional or social variety of a language that differs from the standard form in terms of pronunciation, grammar, vocabulary, and usage. African American Vernacular English (AAVE) is an example of a dialect spoken by African Americans in the United States.

Sociolinguistics is the study of the relationship between language and society, including language variation. It examines how language is used in different social contexts and how it is influenced by factors such as social class, ethnicity, gender, and region.

Sociolinguistic variables are linguistic features that vary according to social factors such as region, social class, ethnicity, and gender. The pronunciation of the word 'car', the use of the word 'ain't', and the use of the word 'y'all' are all examples of sociolinguistic variables.

Language change is the process by which languages change over time. It can involve changes in pronunciation, grammar, vocabulary, and usage. Language change is a natural and ongoing process that affects all languages.

Historical sound changes are changes in the pronunciation of words that occur over time. The Great Vowel Shift, the loss of the letter 'h' in English, and the addition of the letter 's' to the end of words in English are all examples of historical sound changes.

Neologism, lexical innovation, and word formation are all terms for the process by which new words are created. This can occur through various mechanisms, such as borrowing from other languages, blending existing words, or creating new words from scratch.

A neologism is a new word or expression that has recently been introduced into a language. Smartphone is an example of a neologism, as it is a relatively new word that was coined to describe a type of mobile phone.

Semantic change, lexical change, and meaning shift are all terms for the process by which words change their meaning over time. This can occur through various mechanisms, such as metaphor, metonymy, and euphemism.

Semantic change is the process by which words change their meaning over time. The word 'gay' used to mean 'happy', the word 'nice' used to mean 'foolish', and the word 'awful' used to mean 'full of awe' are all examples of semantic change.

Linguistic anthropology, sociolinguistics, and cultural linguistics are all terms for the study of the relationship between language and culture. These fields examine how language is used to express cultural values, beliefs, and practices.

Cultural linguistic studies examine the relationship between language and culture. A study of the use of metaphors in a particular language, a study of the relationship between language and social class, and a study of the use of language in religious rituals are all examples of cultural linguistic studies.

Cognitive linguistics, psycholinguistics, and linguistic psychology are all terms for the study of the relationship between language and thought. These fields examine how language influences our thoughts, beliefs, and understanding of the world.

Cognitive linguistic studies examine the relationship between language and thought. A study of the relationship between language and memory, a study of the use of language in problem-solving, and a study of the relationship between language and emotions are all examples of cognitive linguistic studies.

Gender linguistics, sociolinguistics of gender, and feminist linguistics are all terms for the study of the relationship between language and gender. These fields examine how language is used to construct and maintain gender roles and identities.