When a person speaks, brain waves and blood flow are especially likely to reveal increased activity in the?

The left hemisphere of the brain.

Explanation:

The brain is divided by scientist in left and right hemisphere. Generally, the left hemisphere controls the opposite side of the body (right side). Some tasks require both side of the brain.

Studies show that the left hemisphere of the brain participate or control activities related to language, such as speaking, reading, thinking and reasoning.

Hello there

the answer to your question is

left hemisphere

Best Regards Queen Z