'Who can translate what is being said into English' would be my response because you are presumably taking something said in another language and then translating it inTO a different language, English. 'Is been' is not acceptable. It is either had been or has/have been depending on the tense you wish to use

Hi Frank, The first one is correct because it's the Present Continuous tense hence the 'being' and because there's a converting aspect to it the preposition 'into' is better than 'in' The third one would be correct if it were 'Who can translate what has been said into English'.