Great question!  English is the working language of our team... you don't have to be a native speaker but you do need to have a high quality level in English. I would say if you work in the teams in Europe and America then 90% of the content you work with is going to be English.  So if you're trying to do a content analysis, it's in English.  So we're looking at stuff in preparation for translation and our working content is typically English. 

If you work in the team in APAC then you do need to have fluency in Japanese, Chinese or Korean as these are the main languages we work in with the team in Asia. 

But to answer the question, for the main part English is the main working language and that is the requirement for working in the CQP team.