It's in the Vocabulary section of A Primer of Medieval Latin by Charles H. Beeson.

It's our old friend papa meaning 'father,' common to many languages. Some think this an argument for common descent. See: http://www.newscientist.com/article.ns?id=dn6188 Others say it's convergent evolution: http://www.sussex.ac.uk/linguistics/documents/where_do_mama2.pdf

WARNING: The second link is a pdf.