i think it makes sense for him to. He delt with all three languages on a regular basis thgouh his partnership with Chewie & his job as a smuggler. It's not unusual to meet someone who can at least understand another language if they regularly deal with it (an example being many people who live in the southwest & are native english speakers can at least understand a fair amount of spanish just by being in contact with so much of it).
Plus, it shows he's not some unitelligent drug runner, but a cunning/streetsmart smuggler.