>In order to clarify the check: Epstein asked Noam to develop a linguistic challenge that Epstein wished to establish as a regular prize. Noam worked on it, and Epstein sent a check for US$20,000 as payment. Epstein’s office contacted me to arrange for the check to be sent to our home address.

This part honestly makes no sense. There is no 'Chomsky linguistic challenge'. I guess the claim is that Chomsky was paid as a consultant to develop the supposed challenge which was then to be administered by Epstein (who – guess what – did nothing of the sort). But it sounds an awful lot like an entirely spurious reason for sending someone $20k.