In Savage Worlds Deluxe, the Jack-Of-All-Trades edge grants the following benefit:
Any time he makes an unskilled roll for a Smarts-based skill, he may do so at d4 instead of the usual d4–2.
Languages fit under the category "Knowledge (Smarts)", and so are Smarts-based skills. The chart for Languages says:
d4: The character can read, write, and speak common words and phrases
Does this mean Jack-Of-All-Trades edge provide the ability to read/write/speak common words and phrases in any language?
Jack of All Trades does not give characters training in Smarts skills. It does not grant a skill die type. What the Edge does is negate the Untrained penalty when rolling for those skills - the character is still Untrained and may not be allowed to roll depending upon the situation, skill, and GM adjudication.
Jack of All Trades could allow a would-be linguist to slowly puzzle out simple phrases, assuming appropriate references. But the character does not have training in the language and shouldn't expect to be able to communicate.
While it seems to make little sense, the rules as written do not exclude languages (or any Knowledge) from that list, which means that yes, they can ask "Where is the bathroom" in any language.
It should be noted that this isn't quite as strong as it appears, given that the number of languages a character is exposed to during a usual Savage Worlds adventure isn't too high, and the Jack-of-all-Trades isn't capable of providing more functionality than any tourist phrasebook.
