Maryam or
Mariam is both the Aramaic and Arabic form of
Miriam.
My great-grandmother's name is
Maryam and we pronounce it "MUHR-yum". Arabs mostly pronounce it "MAHR-yam"; it is true that in both instances, there is a very slight enlongation to the "ee" sound, but it is very slight and doesn't really warrant a syllable of its own when sounded out.