He only voiced both FOC & AOE Grimlock in Rise of the Dark Spark in addtion to Lockdown. I'm more Mad that Grimlock is not voiced by John DiMaggio, let alone the Dinobots didnt talk.
Nope, but Skrillex is providing some of the Dinobots' roar sound effects. Skrillex Saving 'Craziest Skrillex Sounds' for 'Transformers' Movie | SPIN | Music News
As Optimus would explain in the '07 movie "We learnt earth languages thru the World Wide Web". That's the most convenient explanation that we can get.
With them not talking it almost seemed to make their bot modes irrelevant. They basically came off the way Scorponok and Ravage did, just running around chomping and trampling. It was a stark contrast to the increased dialogue from everyone else, which really made them seem like just beasts.
I, personally, liked them not speaking. Am I saying I didn't want at least one "Me Grimlock"? Hell no. But, I wasn't bothered. They were beasts and intended to be. Warriors that would turn the tide of the fight. Them not speaking actually gave them an ancient vibe. That's how I felt, anyways.