La la la, first post...
According to Scottish and Irish Gaelic, a lot of the time 'mh' is pronounced approximately 'v' (very approximately!) - a friend of mine is called Mhairidh, which is pronounced Varri. Causes endless confusion for people who speak no Gaelic! (I always thought Celtic described the culture, the people etc etc, and the languages are Irish Gaelic and Scottish Gaelic, and variants thereof - though I may be wrong. Anyone?)
And I've always heard Samhain pronounced "Sow'n".
That's my two cents!