Aegish (capitalized) is an old spoken language employed by the Aegis race in Metal Shadow. It is the basis for the Modern Tongue. Its origins are completely unknown, which suggests that the Aegis may not have been of Deepelgian origin. No written Aegish text exists; the only records are in translations made by the Elves written in Elvish.

Aegish follows the exact same rules as the English language, with some differentiation: progressive tenses are omitted, adjectives and nouns/adverbs and verbs are combined, and words are spelled backward and/or with letters mixed around.

It is believed that the Aegis mostly stopped using the language after their migration to Gilta Nnea.