FWIW, a native speaker of English would not say “ma'ams”. The word “ma'am” is an elided form of “madam[e]” from the French “ma dame”; “madam” is pluralized as “mesdames” from the French “mes dames”. Not many people would say “mesdames”, though; instead they'd say “ladies”, even though the singular “lady” is only used as a vocative absolute in slang.