The 'J' is pronounced as the English 'yay,' and 'ja' means 'yes.' To see someone say 'yesyesyesyes' really doesn't hit me as being funny, but someone who tries to act extremely stupid.
I've encountered many people who prefer their own language above the English and doesn't want to hide it. I don't like such things much, therefore that I will remind again that this is an English forum.
As for Warcraft 4... well, I don't think much will appear of it. If it will, I don't think I'll be getting it. Warcraft III was a nice change for a time for me, but I don't tend to play much games like that.