Oh well, as for myself I don't care about doing it in English or Spanish/Catalan. I'm not really sure about the intended audience anyway, but I can try to fit the needs.
The people that I know who are already planning to come i think that can take talks in any of these languages. If you plan that people who come from abroad attend to these talks, it would be good if they were in english, if you plan to make it merely local, I guess it will be better in local languages. (I say that because I saw there's people coming from France/Italy on the wiki page).
About the Qt talk, I understand you prefer to have someone from nokia. If you want us to do the talk anyway, ping me asap (if possible to the mail, because i can't be all the time refreshing this page).

Anyway, I'll assign the KDE on maemo talk to us and add a kdevelop 4 one. I'll say it's going to be done by KDE Spain, when we decide who is going to do the talks i'll update the wiki.

If you need anything else just tell me