The language is 'unfamiliar to' him. [=he does not know the language at all]
His 'unfamiliarity' with the language made the trip very challenging.
He gets nervous when he is in 'unfamiliar' surroundings.
(..) No, no, no. - Push that in. No, the other... - Here? This one here? - What was that? Taser webs? I don't want Taser webs. You seem to be unfamiliar with your web-shooter settings. Would you like to run a refresher course? - No. Just... You choose. WOMAN : (..)2017 Spider-Man: Homecoming