Association with focus has, since Jackendoff’s (1972) dissertation, been the object of intense study. Most researchers, however, have concentrated on explaining the semantic variability of only and even, whose truth conditions vary with the position of focus. I take as my starting point another property of associating expressions. Both only and even restrict the distribution of focus, a property that, I argue, they share with a range of other lexical items. But, while only and even take a single argument and require there to be a focus somewhere inside that argument, expressions like adversative but and let alone take two arguments, thereby associating with two foci.
Associating expressions, of both the one- and two-place varieties, have two things in common. First, they are crosscategorial in their syntax, taking arguments of a variety of different types. Second, they evoke multiple alternatives — different possible answer to a question. Together, these two independent properties of associating expressions interact with the question under discussion (Roberts 1996, 2004) to give rise to the restriction on the distribution of focus. My approach to association with focus departs from previous ones in important ways. Associating expressions neither make reference to focus in their lexical entry (Rooth 1985, 1992, 1996b) nor to the question under discussion (Beaver and Clark 2008), providing a more satisfying answer to the question of why only some expressions associate with focus.