It reminds me of this weird theory about proto-Castillan. According to some scholars, the change from initial /f/ in Latin to /h/ in Spanish could have been caused by the bad teeth of the speakers of lore, a phenomenon ultimately due to the water quality in some areas.
https://en.wikipedia.org/wiki/Phonetic_change_%22f_%E2%86%92...
Needless to say I've always found this hypothesis doesn't really hold water...