Under the E-Commerce Regulations, an ISP can escape liability for content because it is a mere conduit.

Conduit in the figurative sense: the OED says

4. fig. The channel or medium by which anything (e.g. knowledge, influence, wealth, etc.) is conveyed;

But currently in the USA, there is an argument as to whether an interpreter or translator is a mere conduit.

I suppose that’s how some customers see us.

When the police use an interpreter in an interrogation and do not record the defendant’s words but only the translation of them into English, can the interpreter be challenged legally? Lawrence Solan writes in his Balkinization blog:

An interesting question concerning forensic linguistics is making its way through the appellate courts: When the police use an interpreter during an interview (or interrogation) of a suspect who later becomes a defendant in a prosecution, and the defendant’s words in her original language are not recorded, does the defendant have a constitutional right to confront the interpreter? As a cost-saving measure, more and more law enforcement agencies, and some courts, have been retaining services that interpret the interview over the telephone. One of them, Language Line Solutions. http://www.languageline.com/, has found itself in the middle of this constitutional question.
…
courts should be more realistic in their understanding of what interpreters and translators can do. First, courts should stop relying on the “conduit” theory of translation. Compare two reputable translations of any work of literature. They will be similar in some ways, different in others. To the extent that word choice matters in the context of a criminal prosecution, nuanced differences may affect a case’s outcome. Second, interpreters make errors. The legal system should recognize this. Third, courts should not accept as accurate representations that the entire professional staff of a private firm retained by the government is dispassionate and of high professional character. Surely the defendant need not accept such representations.

Solan recommends that at least the original statements should be recorded as potential evidence.