[steven]

I will argue with you that あい is not spoken as two distinct syllables. It is one syllable. My point was that while the sound may not gllllllllllieeeeede like so many vowels in the English language, but that they combine to create a vowel outside of the "5 vowels of Japanese" that people like to talk about.

I will also argue that while "ai" might not be a good example of one, dipththongs do exist in Japanese. I want to stress that I did not mean that "あい" is pronounced the same way as English's "eye", but that it is similar.