Artus, a joint; articulate, article.
Audio, I hear; audience, audible.
Augeo, I increase: augment, auctioneer.
Avis, a bird; aviary.
Barba, a beard; barber, barbel, barb.
Bellum, war; bellicose, belligerent, rebellious.
Bibo, I drink; imbibe, winebibber.
Bis, twice; biscuit, bissextile.
Bonus, good; benevolent, bounty.
Brevis, short; brevity, abbreviate, brief.