Ailurin

The language spoken by cats. Ailurin, like some human languages, has words and concepts in common with the Speech: but the number of such concepts and words is much higher in Ailurin than in most other Earthly languages, with the possible exception of those languages spoken (or sung) by cetaceans. (TBONWM: OHMWS/TVTQ, WAW)

See also: Cyene: Milk tongues: Wizardry and linguistics.