In Assylum, when Oswin is talking to the Doctor and helping him, how come you hear her real voice,(As does he, Amy and Rory) but at the end,when he finds her she's talking Dalek?

There's been a few threads on this, around the time the episode first aired.

The accepted explanation seems to be that the voice we heard was coming from the Dalek's communication systems, not from someone speaking directly into a microphone, so it can be whatever it likes. Much as she was able to play 'Carmen' despite being wired into a Dalek shell, what we heard was what she wanted to hear, the sounds she thought she was making.

When the Doctor encountered her, she spoke directly through the Dalek synthesisers.

I don't know about you, but I can listen along to a song and 'hear' myself singing in my head, but when I actually open my mouth it turns into a horrible squeal. It's a bit like that.

Cheers for that, to be honest It completely by passed me the first time round It was only when I watched the episode for the second time last night that I picked up on it..