Sounds like Broca's Aphasia. Symptoms of Broca's Aphasia can run the gamut from a complete inability to speak to problems with fluency, articulation, and word-finding, and is common with TBIs particularly if the left side of the brain is injured. I experienced this early on with my TBI (although my injury was primarily on my right side). I did have speech therapy and that was helpful.

If your doctor is familiar with TBI they will be familiar with this symptom, just describe it to her or him as you have done here.

Best to you as you recover.