The Ilkorin word for “father” derived from primitive ᴹ✶atar[ă], also attested in its plural form edrin (Ety/ATA). It is identical to its Noldorin cognate N. adar having undergone similar phonetic changes from its primitive form, possibly ✱✶atară.
Early Quenya
attu
noun. father
atto
noun. father
atar
noun. father
tatto
noun. father
A word for “father” in the Gnomish Lexicon Slips (PE13/111). In the Gnomish Lexicon of the 1910s itself, G. babi or baba was “mummy, mamma” (GL/21, 57). As pointed out by Gilson, Welden, Hostetter and Wynne, there is a complementary change of {nân “father” >>} G. nân “mother” elsewhere in the Gnomish Lexicon Slips (PE13/115).