It was not clear to me while watching. Do the characters speak English with each other, or does each one simply speaks his/her own language and the others understand?
It is confusing also to understand since their environment speak English. Is it just to make the show easier to watch, or is it as if each character speaks his/her own language and we are able to understand it as 'our' language?
I remember there was an episode where Naomi was asked how many languages can she speak. She answered 7, so I believe she counted the mother tongues of her cluster (English, Spanish, German, Icelandic, Hindu, Swahili, Korean). But in a later episode, Riley tells Will that she can speak French, and therefore he can too; shouldn't Naomi count this language as well?