What Is Register in Linguistics?
In linguistics, the register is defined as the way a speaker uses language differently in different circumstances. Think about the words you choose, your tone of voice, even your body language. You probably behave very differently chatting with a friend than you would at a formal dinner party or during a job interview. These variations in formality, also called stylistic variation, are known as registers in linguistics. They are determined by such factors as social occasion, context, purpose, and audience.
Registers are marked by a variety of specialized vocabulary and turns of phrases, colloquialisms and the use of jargon, and a difference in intonation and pace; in "The Study of Language," linguist George Yule describes the function of jargon as helping " to create and maintain connections among those who see themselves as 'insiders' in some way and to exclude 'outsiders.'"
Registers are used in all forms of communication, including written, spoken, and signed. Depending on grammar, syntax, and tone, the register may be extremely rigid or very intimate. You don't even need to use an actual word to communicate effectively. A huff of exasperation during a debate or a grin while signing "hello" speaks volumes.
Source:
https://www.thoughtco.com/register-language-style-1692038
