Filler (linguistics) in the context of "Wh-movement"

Formulaic language (previously known as automatic speech or embolalia) is a linguistic term for verbal expressions that are fixed in form, often non-literal in meaning, with attitudinal nuances, and closely related to communicative-pragmatic context.

Along with idioms, expletives, and proverbs, formulaic language includes pause fillers (e.g., "Like", "Er", or "Uhm") and conversational speech formulas (e.g., "You've got to be kidding", "Excuse me?", or "Hang on a minute").

An interjection is a word or expression that occurs as an utterance on its own and expresses a spontaneous feeling, situation or reaction. It is a diverse category, with many different types, such as exclamations (ouch!, wow!), curses (damn!), greetings (hey, bye), response particles (okay, oh!, m-hm, huh?), hesitation markers (uh, er, um), and other words (stop, cool). Due to its diverse nature, the category of interjections partly overlaps with a few other categories like profanities, discourse markers, and fillers. The use and linguistic discussion of interjections can be traced historically through the Greek and Latin Modistae over many centuries.

A speech disfluency, also spelled speech dysfluency, is any of various breaks, irregularities, or non-lexical vocables which occur within the flow of otherwise fluent speech. These include "false starts", i.e. words and sentences that are cut off mid-utterance; phrases that are restarted or repeated, and repeated syllables; "fillers", i.e. grunts, and non-lexical or semiarticulate utterances such as uh, erm, um, and hmm, and, in English, well, so, I mean, and like; and "repaired" utterances, i.e. instances of speakers correcting their own slips of the tongue or mispronunciations (before anyone else gets a chance to).