Dispatcher reported a communication and regulatory flight following issue with a flight crew experiencing an airspeed unreliable malfunction. The flight diverted to an alternate airport.

Narrative

Received ACARs message from crew requesting a call; about 150nm South of ZZZ. Tried to contact them several times with no success. Messaged them to try another frequency; involved AIRINC to also have them try to contact aircraft on frequency. Received another ACARS from crew saying airspeed unreliable; diverting to ZZZ1. I asked if they were declaring and did not receive an answer. At this point they informed via ACARS ZZZ1 was not an option and they were diverting to ZZZ. They requested landing data which I sent over along with updated release; notams; etc. They eventually did acknowledge receipt of landing data. As soon as they were clear of the runway I requested to Captain to call to address communication issues. He had told me he saw the frequency changes for AIRINC and ACARS messages coming in; however both his airspeed and pitch indications were unreliable making the cockpit very task saturated. With unreliable indications he thought the most prudent course of action was to get on the ground ASAP using Captains priority authority.