Final answer:
Broca's area is the part of the brain that is primarily involved in controlling speech, responsible for speech articulation, and its impairment leads to expressive aphasia. It is located anterior to the motor cortex in the frontal lobe.
Step-by-step explanation:
The brain area primarily involved with controlling speech is D. Broca's area. Located in the lateral aspect of the frontal lobe, just anterior to the region of the motor cortex associated with the head and neck, Broca's area is responsible for controlling the movements necessary for speech production.
This region is named after Pierre Paul Broca, a French surgeon and anatomist. In the case of damage to this area, a person might experience expressive aphasia, which impacts their ability to articulate speech, often resulting in non-fluent, halting speech and grammatical issues.
In contrast, Wernicke's area is associated with the comprehension of speech and is located in the posterior section of the superior temporal gyrus in the temporal lobe.