I'm afraid it's not one of my better known languages.

It does not seem to be related to any known language.

There are also several words that do not appear to be from any known language.

Jim, I love your stuff - when it's in a known language.

Church stared as if he had just heard some un- known language.

People from another world are not likely to speak English or any other known language.

Wasn't in any known language, so it had to be a prank.

He spoke no known language at the time he was brought in.

For example, the numbers from one to ten seemingly have no relation to any known language.

"He does not speak any known language, my lord," I said.