Speaking with IGN, J.J. Abrams, known for his work on the revamp of Star Trek and Star Wars, acknowledged that the Hollywood adaptation of Portal was "still very much in development" along with an adaptation of Half-Life. Not only that, Abrams confirmed that a more substantive announcement concerning the Portal film could be expected in the near future.
Abrams said that he and his people are still in communication with the Valve team. "We have a meeting coming up next week with Valve, we're very active, I'm hoping that there will be a Portal announcement fairly soon," Abrams said. Though pressed for more details, Abrams gave an expectedly vague response that merely hinted that there were some interesting ideas being bandied about the writer's room.
Nothing is really known at this point about either the Portal or Half-Life films except that, apparently, they are still very much alive and well despite virtual silence since their initial announcement at DICE 2013.