'mah-' is US English, not English :P It's 'mah' in one country.

p.s. Seems every day on here I'm reminding people from the US that their country is not the world, their version of English is spoken and spelt in just one country, etc etc etc. Maybe I should give up doing that.

The most classic maybe was a linguist (yes, amazing) who on her blog was gloating that her variety of US English was particularly rich, in having almost every vowel sound in English. I looked at her list.. it didn't include the 'o' sound in 'pot'..