when I read the comics I just can't imagine it in the classic cartoon Donald voice. But I did once have a co-worker borrow one of my Carl Barks collections and she said she had a hard time reading it because she couldn't stop reading it in his voice and some sentences just didn't make sense. Glad my relationship with donald is mostly through comics not cartoons.
Oh? That's odd -- imagining the characters speaking with their cartoon voices has never bothered me, except for one, Scrooge, whose voice I imagined higher-pitched (more like his French voice actor: here's an episode of DuckTales in French if you want to hear for yourself)
I never hear the cartoon characters' voices in my head when I read comics. In a similar thread on the DCF, I got the impression that I was in the minority. As I asked there, when you read the transcript of a speech by, say, President Obama, do you hear his voice?
The brazilian Donald's voice in DuckTales was so diferent from the other cartoons that it was easy to understand him. Also, I think it would be nice in a more barksian aproach of the character.