We are hoping to host a call with 30-40 participants from 10 different countries around the world. I'm wondering if there are any functions built in to allow live translation or closed captioning in other languages during the meeting?
While GoToMeeting currently supports 8+ languages through the interface (including French and Spanish) it does not have a closed captioning system or the ability to broadcast different audio feeds. You might consider setting up a scroll bar on your screen with interpreters creating the captioning, or pre-programming the feeds beforehand or use the built-in CC for PowerPoint or Google Slides.
I am using GoToMeeting to host large online meetings for around 100 participants. Some will have limited English so we will need simultaneous translation.
Is there any option allowing participants to choose between two separate audio tracks (the speaker in English, and translator in second language or vice versa)?
There is currently only one integrated audio feed available for GoToMeeting, though you could consider using a closed caption system such as the built-in options for PowerPoint / Google, synchronized with the presentation slides.