Absolutely, this. I see this all the time with colleagues that don't speak English too well (I'm not in an English speaking country, but development offices often use English)

I'm not talking about people who can't express themselves or can't understand, merely that they haven't mastered it - use clumsy wording, or have a thick accent. These are often some of the most technically capable and talented people I've worked with, but also typically are not perceived as such by others, and im ashamed to say, working together with them would often result on the credit being placed unduly on myself.