'babby' is a dialectal variant of English 'baby', ultimately from Middle English 'babi' or 'babie', formed by infantile reduplication based on baby talk (syllable 'ba-').

'babby' developed alongside Middle English 'babi'/'babie' and the standard form 'baby'; the spelling with -bb- appears in several regional dialects and informal spellings, preserving the reduplicated consonant pattern in some pronunciations.

Initially it meant 'infant' in the same sense as 'baby'; this basic meaning has been retained, though 'babby' remains chiefly dialectal or informal.