Don't confuse "interpreters" with "translators."

Translators write. Interpreters speak. Interpreters are usually also translators, but most translators are not interpreters, because interpreting requires specialized training different from that of a translator, as well as a higher degree of spoken fluency.

If you see somebody in a booth at a conference, speaking into a microphone so that people who don't understand the presenter's language can listen to the talk and understand it, that person is an interpreter, not (necessarily) a translator.

If you need a birth certificate translated into a foreign language in order to get a visa, you would contact a translator, not an interpreter.

Almost every single conference website I have ever seen makes this basic mistake. Now you know how to avoid it.