In particular /w~b/ or other sounds that could be transcribed as <w> or <b>.

Background: A person gave his name variously as 'John Barosa' or 'John Warosa' in writing from which I figured that in his language either there is one phone that is similar to both /w/ and /b/ in English or another language that uses the Latin alphabet, or [w] and [b] are allophonic. I would like to find out which language(s) that might be.

I would have liked to make separate questions for the resource and for the finding of the language but I wasn't able to because of the 40min cooldown period.