yes, you are correct in that dysarthria is difficulty speaking, where their speech is very difficult to understand, but present nontheless. Very common after CVA, etc. Aphasia is the inability to produce or comprehend speech. There is also Expressive Aphasia, in which pt's have difficulty finding the right words, and their speech is broken, halted, and difficult. I believe Expressive Aphasia is also called Broca's aphasia. Hope I helped some. Good luck to you