I can only recall One other story here at FIM Fiction where the human protagonist had that disability.
Bravo. Following.

nice work.

Been awhile since I've seen a mute mc in a fimifc.

You put (2nd person PoV) in the description, instead of just putting the Second Person tag into the actual tag list.

You weren't much of a conversationalist anyway, but you did throw in the occasional gesture that she figured out how to interpret.

You'd think ponies would have some sort of a sign language, or something...

10205623
When they have magic to grant mute ponies the gift of speech, I doubt they'd have the need to develop Sign Language in the first place.