Just tell your Dr. the symptoms, exactly what you've told us here and s/he will diagnose it. It's probably aphasia... but Dr.'s typically don't like it when you go in and tell them what you have...

Since the auto accident and concussion I sustained I have suffered from aphasia. It's getting better, but it's 3.5+ years since... and I'm taking a lot of hormones that were caused by deficiencies from the concussion... and it still happens! It's frustrating but it's definitely a common symptom of a tbi.