ABSTRACT
What does public language do for us? There is a common, easy answer which, though not incorrect, is subtly misleading. The easy answer is that language helps us to communicate ideas. It lets other human beings profit from what we know, and it enables us to profit from what they know. This is surely true, and it locates one major wellspring of our rather unique kind of cognitive success. However, the emphasis on language as a medium of communication tends to blind us to a subtler but equally potent role: the role of language as a tool 1 that alters the nature of the computational tasks involved in various kinds of problem solving.
