Hi Cyril,
>- is the workshop attendance mandatory if we send a paper for the
workshop proceedings (the cost could be important for us)? If so, do
colleagues of mine can present our work (they have a paper in NAACL
but they did not work on SemEval), even if they are not co-author?
Presence is not mandatory and a colleague who is not a co-author can present the work - generally system papers are likely to be presented as posters. As far as I know, *SEM will follow the standard procedure of requiring that at least one author register for the event. You can write to SemEval organizers to confirm that if you want.
- is there any indication about registration: SemEval workshop fees, StarSem conference fees, etc.?
The registration will be done through NAACL - fees and etc are on the website. If you have any more specific question about that, please ask Suresh/Deniz.
Best,
Lucia