Can anyone who speaks two languages be a translator?

Yes and no. Translating is a specific skill which you need two languages to have, but having two languages by itself doesn’t mean you’d make a good translator. A good translator will be skilled at putting sentences in one language into sentences which have the same impact and sound natural in another language. A few people with two languages are naturals at this. Most people are not and have to learn how to do it, for instance at university. It also helps if you have in-depth knowledge of a subject area such as finance, law, economics, chemistry, medicine or software, as a lot of translation work is specialist work.
Perhaps surprisingly, some people who were brought up bilingual and are extremely competent in two languages do not make good translators. Although being a good translator includes having a very good understanding of more than one language, this is not the only skill involved.
Do I need a specialist?