A while ago, SE briefly introduced a built-in feature where a user can type:
translate: [words in any language]
...and the Feeds user would respond with an English translation of whatever was typed.
This feature was curtailed, however, when some users began abusing the feature by immediately deleting the translation requests to get the Feeds user to "participate" in conversations; deleting the translate message would cause the response to be deleted as well.
It was later on disabled for non-moderators due to its apparent limited use (no international sites existed at the time), and a long time later, it appears to have been completely removed since it no longer responds to moderators (who probably didn't use it very much).
Anyway, we now have an all-language chat room created by an SE employee for users interested in internationalization, where users can talk in any language they like. In this room, it would be beneficial to have this feature re-enabled (while it wasn't really beneficial when all chat rooms were in English, let alone one specific language).
Since the requested bot is only planned to be used in this room, which is actively monitored by an employee, abuse can easily be dealt with. (It was hard to deal with network-wide.)
Can we please have a bot that reinstates this functionality in chat, detecting languages and posting English translations of any language into the room? (As I said, from what I can tell, it looks like the code for the feature was removed entirely from the chat system, and it could take a long time to reintroduce it.)