Interjections are words or vocal gestures that can server a variety of purposes, including:
- indicate an emotion: Ow/ouch (pain), Whew/phew/shew!" (relief), "Aw!" (embarrassment, compassion, "how cute"
- indicate an opinion: "uh-huh/mm-hmm" (yes), "uh-uh" (no), "oh-oh/uh-oh! (something's wrong)
- call attention: psst
- give a command: sh/shush (be quite!)
- fill pauses while speaking: um, er, like, so
While some interjections may be included within complete sentences, they generally do not have any grammatical relationship with other words in the sentence.