Between 2:59 and 3:25 of the song Charlie Brown by Coldplay (song link) some sort of vocal electronic sound can be heard. It is not the first time I hear this kind of sound and I was wondering how is it achieved.
It sounds like a sample being played faster than originally recorded. There are a couple of videos on Youtube that feature the intro played back at different speeds:
Beyond that, the sample is washed out with a lush reverb, set with a pretty much 100% wet/effected signal. The sample is also rigorously EQ'd with all low frequencies removed.