What are the pronunciation differences between speaking and singing Japanese? [closed]

Question

I've noticed that some pronunciation is different in singing than in speaking. For example, I often hear を pronounced as /wo/ rather than /o/.

What other pronunciation differences are there?

That is a lot of questions! At least, as for “aishteru,” it is called muted vowels or devoiced vowels, and this phenomenon is not specific to songs. See this question and other questions listed under “Linked” on the right of that webpage.
You are welcome. Correction in my previous comment: muted vowels → mute vowels.
I really don't think there are such "rules" so that we can answer this. For example, listen to this: youtube.com/watch?v=557LCPYdqvA Every "devoiced vowel" in the song, from start to finish, is voiced. As hi ta e isoge / Nokos hi ta mono wa / Mit su kete kureru. It just depends on the singer and style.
Rather than vote to close, I tried to improve the question. Please feel free to roll my changes back if you think they were out of line.
Sorry, I voted to close because no matter how well the question is phrased, singing is an art, which means that the decisions about pronunciation (or anything else) that any one singer might make are completely open to their personal interpretation (and culture... and style...etc...) and can't be codified. Answers can only be long lists of various things that individuals have heard in songs they've listened to, but without any way to verify how common, pervasive, or standard they might be. This question would be answered more accurately, and be more fun, with practical karaoke experimentation.

Eric Dong · Accepted Answer · 2013-02-02 00:31:32Z

I'm not expert, but from the many Japanese songs I've heard it's mainly

Pronouncing お as "oh" (i.e. slightly diphthongized) especially in songs where half the lyrics are English lol
Pronouncing を as うぉ. This is probably due more to the fact that it is in the W-line, and old pronunciations stick better in slowly and carefully articulated things like poems and songs.
A distinction between おう and おお, and separation of いい Again, this is probably due to conservative pronunciation. おう was always a genuine long vowel, while most instances of おお came from おを or おほ. This is most obvious in the word おおきい which is often pronounced おをきひ.
Not discriminating between different allophones of ん, instead only "n" is used. This is usually because "n" fills a mora better, and Japanese mora, not syllables, are usually matched with the notes.
Again a mora issue, the っ is pronounced a bit differently. In speech 強がっても would be (tsu-yo-ga-*-te-mo) but in song it would be more like (tsu-yo-ga-att-te-mo), almost as if it were つよがっあっても　.

That's all my limited experience has noticed.

がっあ was to emphasize that があ wasn't a long vowel. I thought that っ in isolation meant glottal stop?

closed as not constructive by istrasci, Dono, ssb, fefe, Dave M G Feb 5 at 6:33