He speaks English and Romanian fluently. In Captain America: Civil War (2016) he actually speaks Romanian in the first scene set in Bucharest, Romania.
It was like a huge master class every day in rehearsal with [director] Bob Falls and [actor] Liev Schreiber. I spent the whole time at the
table taking notes on everything Liev was saying: Quoting Shakespeare and how [the play "Talk Radio"] was similar to this or that play. I'd come in and be so hyped up and he'd be like, "Listen. It's all great, but you gotta figure out what you want here and why." [2007]