Good beat for me. About 1/4 of my songs are in German (plus 1 in French) and I can't understand a thing. But the melody is so good that I can't pass it up.
Good beat is what hooks me into the song and like it. Good lyrics are what cause me to feel a connection with the song and have it become one of my favorites. If it doesn't have a beat I like though it will be harder for the lyrics to make up for that. Both play an important role but I have to go with beat.