For dating & ringtone offers is it better to target english or the entire set of languages that is shown up when starting a new campaign?
It depends what offers you are promoting. I only work with US ad networks that usually require US traffic, so English works for me. If you can write good ads in other languages and have applicable offers, you could try it out. Some people I know have had good luck with Italy.
Ads should be the same language the website is. If you have multilanguage, your adwords program should have different campains for different language.
I think it's better to use specific languages for specific targets. I will know exact statistic for customer's demand.