In the upper right hand, from the menu editor, choose screen options. Show classes. Then you can add classes to each link.
No way to do this dynamically in CSS that I know of – you could definitely do it with jQuery though.
Yeah, I figured we couldn’t do it that way. Currently I just put bold tags on the second words, but I would need a better fix. Eventually my client is going to change navigation on his own, and I would rather not teach my clients how to bold text. Even that simple idea is complicated to some…