Dear Raya Al-Naimi , Yes, I suppose, especially for those researchers who haven’t studied English as a second or foreign language. But as much as RG reinforces English, it makes other languages, Arabic, for instance, almost sink into oblivion.
In my opinion the function of RG is not to improve one's English but to help researchers disseminata their work, establish new professional contacts, inform about the latest research, etc. There are other platforms to increase English vocabulary.
By the way, did the question mean the increase in 'research-related English vocabulary'?
Thank you Dorota Werbińska for you opinion, yes I meant 'research-related English vocabulary, there are many English related subjects, in addition to quotations that I have never heard before
In that case (research-related vocabulary and skills) it might work for those whose academic activity is only restricted to RG.
In reality, though, most researchers read 'tangible' books, subscribe to journals and write, treating RG as one of the resources but not the main one. At least this is the case with me and my coleagues who are researching.
Perhaps investigating a profile of RG users might be helpful in this respect.