Each character corresponds to a Japanese alphabetic character ... The vowel sounds are as follows: A = Automobile, I = Meet, U = Ooh, E = Hell, O = Stroll 2. Sometimes, the A, I, U, E, O, Ya ...

MacOS is easiest: just hold down the key you want to accent (say, the e) and your options ... you then type the letter you want to accent, and then a character that corresponds to the accent.