Ilk. adda n. “father (hypocoristic)” (Category: Father)
A diminutive form of “father”, similar to English “daddy” (Ety/ATA). Helge Fauskanger suggested it may have developed from primitive *✶attō based on its Quenya equivalent ᴹQ. atto (AL-Ilkorin/adda), but I think that is likelier to be a child’s invention, unrelated to other languages.
Reference ✧ Ety/ATA ✧ “father (hypocoristic)”