Japanese, Many native american languages, Sundanese, Malay, many African languages.
Not to say that sound symbolism of the "ma" sound isn't a real thing, but rather that its adoption for the "mother" word is far from universal, but just frequent enough to be interesting.
I didn't say it was universal, but it's extremely widespread, and more importantly, it's widespread among a diverse set of languages that don't share a common root.
Incidentally, the Wikipedia page for "Mama and papa" says that in Old Japanese the word for "mother" was papa.
Not to say that sound symbolism of the "ma" sound isn't a real thing, but rather that its adoption for the "mother" word is far from universal, but just frequent enough to be interesting.