21 Accents

Amy Walker is an actress, writer, singer and dancer from Seattle, Washington. She gained notoriety with her 21 Accents video, in which she repeats the same sentence 21 times in as many different accents. She has commented in some interviews that performing a convincing accent is as much about assuming the facial expressions and mannerisms of that culture as it is about changing one's voice or intonation.

The video is very funny and you can visit her official site for some more clips on how to learn any accent. She also has a youtube channel. Have fun!