I take it that machine-translated sites (eg google translate tool used on site) would only be listed in the original language?
Yes.
Also any sites where the content is obviously machine translated - ie the content is done in such a poor manner as to make the site unreadable. If the reviewing editor can't even decipher what it is supposed to mean it has no chance.
This doesn't mean that sites that are poorly translated by humans will always be declined either, but the majority of the content should be in a comprehensible form in the language in which it is being reviewed.
Even native English speakers make idiomatic and grammatical mistakes which won't cause the site to be rejected out of hand. If it looks like it was translated from Spanish to English using a Spanish --> French and then a French --> English dictionary it is probably going to fail any review.