Hi ....I think that the pronounced depends of the letter comes before, for exemple the word ''item'' , the letter ''e'' give a diferent sound. The word ''falam'' because of the letter ''A'', I guess

I guess it's too late to answer this one, but if you meant how both words are pronounced in Portuguese as Portuguese words (i.e. "item" in Portuguese rather than the same word in English) then both Ms become nasalized and sound the same, except that the vowels would be different /eiy/ sort of like 'day' vs. /iao/ sort of like "ciao", or the /ow/ clown. Obviously, if you meant "item" as the English word and pronunciation /ay-tem/, then that would have the 'M' pronounced and would be different than the nasalized /em/ or /am/ equivalents in Portuguese, like "falam".

Yes, Juci is right. Their pronunciation may seem different for the previous vowel.

No, my friend! The letter m has the same pronounces in the two words.