my, Old Irish mo, mu, Welsh fy, Middle Welsh my (from myn), Cornish, Breton ma (which aspirates): *mou, *movo: formed on the analogy of do, du, from the pronomial root me (see mi). Welsh myn or my n- is allied to Zend. mana, Lithuanian manè (for me-né), Church Slavonic mene.
Etymological dictionary of the Gaelic language.
Alexander Gairm Publications.
1982.