'attababy' originates from English, specifically formed by blending 'atta' (a reduced colloquial form appearing in expressions like 'attaboy' originally from 'that's a boy') and 'baby', where 'atta' served as an informal exclamation of approval and 'baby' is used as an affectionate term.

'attababy' changed from the earlier colloquial exclamation 'attaboy' (itself a contraction of 'that's a boy') and similar forms like 'attagirl'; the playful replacement of 'boy'/'girl' by 'baby' produced the modern 'attababy'.

Initially related to the phrase 'that's a boy' used to praise a (male) person; over time it generalized into a casual, affectionate interjection meaning 'well done' or 'good job', usable regardless of gender and often playfully.