Answer:
Cerebral cortex.
Step-by-step explanation:
The cerebral cortex is the structure that contains the cell bodies of neurons, where nerve impulses arrive, which are processed and "returned" with a response to the body. This part of the brain has several subdivisions, each of which has its own specialty and responsibility within the organism. One of these subdivisions is called "speech center", it is in this subdivision that speech processes and articulation of the sound of words are produced.
Because of this, if Jason has difficulty speaking and forming coherent sentences, we can conclude that he must have damage to the cerebral cortex in the region of the speech center.