I'm reading a Chinese manga translation and have come across this note above a panel: 嘰咿—
I'm not sure what it could mean or say in English. Can anyone help me? Thanks!
That looks like onomatopoeia (象声词) so it means exactly what it sounds like: jiyi. In this case though, the 咿 (yi) and the dash (—) are meant to extend the "i" sound, so it's just "jiiiii--" altogether.
嘰/叽 is usually used for small birds chirping, as in the second definition:
If you look at this list of Chinese onomatopoeia, you may notice that a lot of the characters have the mouth radical (口). When you see a single character or multiple characters all with that radical, especially in a manga, it's very likely that it's an onomatopoeia.