Insertion of "y" sound between vowels


I was watching some anime today, and I heard "y" sounds in places I didn't
expect.

Here's a [sound clip (MP3)](http://sandwich.quarplet.com/y.mp3) and my
transcription:

> 私の世界へようこそ。 今やこの世界をコントロールできる唯一の人間だ。

There are two "y" sounds I didn't expect. I'm not sure whether they're
related.

  1. `世界へ` sounds like "sekai ye" rather than "sekai e".
  2. `世界を` sounds like "sekai yo" rather than "sekai (w)o".

Can anyone explain these "y" sounds to me? Are they standard? Common?




In cases 1 and 2, you have two vowels in succession: /ie/ and /io/.

Assuming that

  1. Your articulatory organs cannot jump from one discrete state to another.
  2. You do not generally stop/weaken your breath between words/morae (of course once in a while you have to stop to breathe in)

you will hear the mouth/tongue moving from i->e and i->o, which is what makes
it sound like "ye" and "yo".

For the same reason, I would say that you can't really tell if it's おみやげ or
おみあげ, unless you know, or you ask somebody to articulate clearly, thereby
probably breaking assumption 2 above.




In cases 1 and 2, you have two vowels in succession: /ie/ and /io/.

Assuming that

  1. Your articulatory organs cannot jump from one discrete state to another.
  2. You do not generally stop/weaken your breath between words/morae (of course once in a while you have to stop to breathe in)

you will hear the mouth/tongue moving from i->e and i->o, which is what makes
it sound like "ye" and "yo".

For the same reason, I would say that you can't really tell if it's おみやげ or
おみあげ, unless you know, or you ask somebody to articulate clearly, thereby
probably breaking assumption 2 above.

