I thought would put to gather list of ponyisms here that i know of. This list may be added apon as people give feedback on few ponyisms i miss our just stright don't know about.
Buck: Either seem be use in place of fuck. Is use as general curse word in the show.
Everypony: Is an other word for everybody pretty much just ponyfid.
Hay: Also just meaning hay, the word is also just as curse insted hell.
Nopony: JUst ponfid version of nobody.
Somepony: Just ponfid word for somebody.
Hoof: use in trems like "Let me lend you a hoof" replacing the word hands.
Mare: Adult our Teen Female of the ponyspices
Stallion: Adult our Teen Male of the ponyspices
Fillie: Young Female of the ponyspices
Colt: Young Male of the ponyspices
Mane: There hair ponies skull.
Horse Apples: Curse word usely use by the applefamily, that has same meaning as "crap"
Flying Feather: usely use in wording of "I don't give flying feather" is term use when not applying furmly that don't care abut other perssons statment.
Pony: Simple it just prefures to indvidule of the ponyspices.
Pony Feather: applies frustration with an other individule our objact.
Feather Brain/Head: Means that you dum, applying your head is full of feathers.
Celestia: Usely use insted of god, considring Celestia is considerd as higer dentiy.
This few word i can recall. If you have any ides of what could add to this list please tell me and also give briff explination on what it mean.