Wizarding/Magical Languages

Fairy:

A buzzing like sound used by fairies to communicate among themselves.

Giant:

Spoken by Giants.

Gobbledegook:

Goblin language. e.g. in this, 'bladvak' means axe.

Mermish:

Language used above water by Merfolk, they speak human languages underwater. It sounds like horrible screeching if heard in air.        Dumbledore can speak mermish.

Parseltounge:

Language of snakes. Voldemort, Salazar Slytherin, and Harry Potter can speak it.

Troll:

Crude form of language spoken by Trolls. It consists of grunts. A troll can although be tought a few words of English.