Hi! In Spanish we say "Chau" and sometimes its sounds like "chao". But I agree with Scott when he said it is taken from the Italian word "Ciao". The additional vowels as in "Chauuu" or "Chaooo" are added to make it funnier, they don΄t mean anything else. AS Sandra said, is like saying byeee... It makes no difference to use one vowel or many vowels.
Byeee!!
M
