question about hiragan long vowels

[sakku]

Hello,
I've just started to learn Hiragana. My question is:
Do long vowels come after voiced vowels (with tenten),too?
For example; is があ correct?
Thank you in advance.

[SomeCallMeChris]

The tenten marks voicing on the consonant part of the が mora (syllable). Although there are cases where vowels are devoiced, there's no mark for it in ordinary writing.

Anyway, you can certainly have a long vowel that starts with a voiced more.
があ isn't really a word ... although there is ガー ... which Edict assures me means 'Gar', a type of fish. The katakana dash is also a long vowel, and although I think you won't find a native Japanese word with があ in it, if you did it would be indicating a long あ vowel.

Anyway, どうろ (road) is a long vowel that starts with a voiced mora.

[sakku]

Thank you very much. It really helped. I guess the same rule goes for the ones with circles.
き゚ い is also possible ?
What about youon (combined kanas)? Can we also make them long?

[furrykef]

The handakuten (circle) only occurs in the H group (はひふへほ), to indicate that they are pronounced with a P instead of an H. So き゚ い is not possible because き゚ isn't possible in the first place.

Sometimes pronunciation dictionaries use き゚ to indicate a nasalized G (like the "ng" in English "hang"), but that's about the only place you'll encounter such things.

[sakku]

Yes, I've just realized my mistake.
I meant ぴい, this is possible (theoretically, I don't know if there is such a word)
But when we write Tokyo in Hiragana it is とうきょう and the last part is a combo with long vowel, isn't it? But the first part と and う are two separate sounds?

[Ongakuka]

とう is pronounced とー

えい - the い is not distinct, so it sounds a bit like ええ

があ is another example of the long vowel sound. Although it is not a word it is found in the name 我愛羅（があら） from the popular manga/anime Naruto

[jimbreen]

The katakana dash is also a long vowel, ....

The ー character is not part of katakana. In the post-WWII writing standards, it's used to indicate long vowels in 外来語 written in katakana, but not in other words in katakana such as the scientific names of plants, animals, etc. It's also often used with hiragana when writing some long vowels in dialect words and onomatopoeia. Pre-war it was used more widely with hiragana.

Cheers

Jim

[sakku]

Thank you very much for the replies.