Intermission: Long vowels and gemination
In japanese, "long vowel" doesn't mean what it means when you're talking about english. Japanese long vowels literally last longer.
Japanese also has something called "gemination". Gemination means that the speaker briefly stops on a consonant. In japanese, this adds the same amount of time as using a long vowel. Practice the following to get a hang of the idea:
| Kata | Ka-ta |
| Kaata | Ka-a-ta |
| Katta | Ka-t-ta |
The letter t isn't pronounced twice in the third example. There's a point in time when the mouth stops making the first "a" sound and is in the position of the "t" sound, but the air is blocked. It's not released until the "ta".
Long e is sometimes spelled as ei えい. Not all instances of えい are a long e. But all instances of えい that are a long e can also be pronounced as literally え followed by い. It can sound stiff, but it's still correct. To illustrate:
えい (not a long e): Only pronounced as えい
えい (is a long e): Can be pronounced えい or ええ
Long o is sometimes spelled as ou おう. Not all instances of おう are a long o. Unlike えい, sequences of おう can only be pronounced a certain way, depending on whether it's a long o or not. おう is used this way because it reduces how many words have the same spelling.
おう (not a long o): Only pronounced おう
おう (is a long o): Only pronounced おお
お and う are so close that the distinction between おう and おお might be hard to hear or articulate in casual speech, but the distinction is always intended.
Most instances of おう that are not long o sounds are verb endings. But there's one verb ending where this is not the case: the volitional, taught later.