leanbh can also be an infant
Is "babog" no longer the word for baby?
The FGB defines bábóg as “doll”. (Dinneen also had “little baby” as one of its definitions, presumably as a diminutive of báb.)
As others have said leanbh is a young child. If you wanted to emphasise that it is a tiny baby you would use naíonán or leanbhín.
Can "leanbh" be pronounced "lean-iv" and "lean-oo" , since it is broad?
The Ulster pronunciation is "lyan-oo"