I did not need it either, and from other colleagues who used the feature I heard that is costs a lot of time. Since time is an issue for a lot of people you should think carefully if it is worth it.
Additionally there are some "trigger words" that might actually help you with answering the questions (e.g. "High level xxx" -> Project Charter, not Project Management Plan) and that you might miss in the translation.
You are right. Non English native aspirants must carefully read the question and get the trick of English language before answering questions. I am a French native speaker and suffered with the English. But I advise students in this situation to prepare well with mock questions and identify the language trick before selecting their correct answers. Trying to link with your native language during the exam would be confusing and waste of time.
For the Non English Native speakers whom have the opportunity to choose their native language as an aid language , I think that at the Exam you must refer back to your native language only when you believe that the word or the sentence you don't understand will directly affect your choise but if you are sure that you get the right meaning of the question no need for going back, however you have to balance your time or what are you think?
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