The Sapir-Whorf hypothesis, also known as the linguistic relativity hypothesis, is the idea that the structure of a language affects the way its speakers conceptualize the world. In other words, the language we speak shapes the way we think about reality.

Language is primarily used for communication, expression, and persuasion. Cognition is the mental process of acquiring knowledge and understanding, which is not a function of language.

Psycholinguistics is the study of the relationship between language and the human mind. It investigates how language is processed, produced, and understood by the brain, and how it influences our thoughts, feelings, and behaviors.

Pragmatics is the study of how language is used in social contexts. It investigates how speakers and listeners use language to communicate their intentions, beliefs, and attitudes, and how they interpret the language of others.

A performative utterance is a statement that, when uttered, performs an action. In the example given, the speaker is performing the action of promising to be home by midnight.

Denotation is the literal meaning of a word or phrase. It is the meaning that is agreed upon by the speakers of a language.

Connotation is the emotional or associative meaning of a word or phrase. It is the meaning that is suggested by the word or phrase, in addition to its literal meaning.

A deictic expression is a word or phrase that refers to something in the context of the utterance. In the example given, the speaker is referring to the store that they are going to.

A register is a variety of language that is used in a particular social context. For example, there is a different register that is used in formal settings, such as a business meeting, than in informal settings, such as a conversation with friends.

A dialect is a variety of language that is used by a particular group of people. For example, there are different dialects of English that are spoken in different parts of the world.

An accent is a variety of language that is used in a particular region. For example, there are different accents of English that are spoken in different parts of the world.

An idiolect is a variety of language that is used by a particular individual. It is the unique way that a person speaks, including their pronunciation, grammar, and vocabulary.

Parole is the individual use of language. It is the way that a person speaks, including their pronunciation, grammar, and vocabulary.

Langue is the system of language as a whole. It is the set of rules that govern the use of language, including its grammar, syntax, and vocabulary.

Competence is the knowledge of the rules of language. It is the ability to understand and produce grammatically correct sentences.

Performance is the ability to use language. It is the ability to produce and understand sentences that are grammatically correct and meaningful.