Its a mouthful so you got to break it down into small chunks.
Ro-as in row a boat. Eth - like a mike Tyson S. Lis - like you had more now you have lis. Finally, berger - as in hamburger. Put it all together and you have Roethlisberger. Ironically, its the feminine form of the word "consensual" in Bavarian. Fun little fact.