I'm completely confused. My vowels are not the same as US vowels nor even English vowels. For instance, English people pronounce 'learn' and 'turn' to rhyme exactly, and I do not (Scottish btw).

Therefore, I can't answer because I don't know how you're pronouncing the words you give as examples.

What you need to do is use the International Phonetic Alphabet. But I pronounce 'mana' with two short 'a' vowels of equal length.