What is "Register?"

Perhaps Wikipedia explains well enough this concept when it states that:

In linguistics, a register is a variety of a language used for a particular purpose or in a particular social setting. For example, when speaking in a formal setting contrary to an informal setting, an English speaker may be more likely to use features of prescribed grammar—such as pronouncing words ending in -ing with a velar nasal instead of an alveolar nasal (e.g. "walking", not "walkin'"), choosing more formal words (e.g. father vs. dad, child vs. kid, etc.), and refraining from using words considered nonstandard, such as ain't.

When writing or speaking in an English course, it is expected that students use the "formal" register. In other words, students should express themselves as though they were in an academic or professional situation.

Keywords: tonalité