What languages are good for a future interpreter or translator?

Whichever language you now feel attracted to and want to learn.

To get accustomed to a language, it takes five years, to get fluent, another five. What do you think the world will look like in another ten years? Things change rapidly these days, so follow your instincts and learn the languages you love rather than those who seem profitable. And, besides, language has a lot to do with love: You can't learn a language fluently you actually hate.

A good idea if you haven't chosen a language yet is listening to some songs in the languages you're considering. It gives you a good impression of how the language sounds, and you can decide whether you can master the pronunciation or not.

Depends on what sort of languages you like and are good at. As long as you avoid the very obscure languages you will usually be in work with most languages.

Try Spanish, Mandarin, German, French, one of the (Asian) Indian languages, Russian, Arabic.

Note that, in Britain at least, an "interpreter" is one who translates word of mouth on the spot, immediately, for police, and court cases, and for customs officials, and similar, whereas a "translator" translates the written word.

Arabic, because there aren't enough interpreters or translators who know Arabic. Were you able to attend a school of Arabic Studies, you'll learn to speak, read, and write in Arabic and you'll be recruited by companies or governments to be an interpreter or a translator. My brother did this and he earns a lot of money because of the need of interpreters and translators. It's a difficult course of study, and my brother graduated from the School of Arabic Studies in Bikfaya, Lebanon with honors and he was the top graduate in his class. I wouldn't go to any school in the Middle Eastern countries now, as one never knows if one will become a target of a terrorist.

I suggest going to Georgetown University and enrolling in the Department of Arabic and Islamic Studies. https://arabic.georgetown.edu/ You will receive the best training and gain contacts that will become a valuable asset. Most likely, you'll be recruited by the U.S. State Department or another governmental agency after or before you graduate as the need for interpreters and translators is very high, especially for those who also have knowledge of Arabic culture as well as the language.

Whatever language you grew up speaking, plus English. There are virtually no interpreters or translators using a language they learned in school.

Kiswahili, North Korean

Sumerian, Aramaic, Ancient Hebrew, Koine Greek...

Arabic, Spanish too but I would also major in another language because it makes you more marketable.

Portuguese.

Spanish, Mandarin Chinese, Japanese, and Arabic should all be in demand over the next few years.

Arabic, Mandarin Chinese, Spanish, Russian, German and Hindi.