pronunciation - 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) 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?

Answer

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.