FWIW, some (most? all? the one's I've heard, at any rate) Spanish dialects pronounce the letter 'f' as a voiceless bilabial fricative (I almost wrote 'phricativ

FWIW, some (most? all? the one's I've heard, at any rate) Spanish dialects pronounce the letter 'f' as a voiceless bilabial fricative (I almost wrote 'phricative'). E.g. fotografia (sorry about the missing accent). The letters 'b' and the 'v' are pronounced in Spanish as voiced bilabial fricatives after a vowel, and as stops after a nasal consonant (which in that position will be pronounced as [m]), and generally in utterance-initial position.