Unlike most other languages, the five vowels are always pronounced the same way in Japanese.

a = "ah"
i = "ee" (as in TEETH)
u = "ou" (as in YOU)
e = "eh"
o = "oh"

and then combinations of vowels naturally follow

For example: ai = "ah ee"

If we can learn Katakana first we can use the fact that katakana is also always pronounced the same way to help us pronounce Japanese words correctly.

If you have any questions or comments about pronouncing Japanese please post them here...