Final answer:
The prefrontal cortex is the brain region responsible for understanding language and inhibiting the accidental use of profanity, as indicated by brain scans like PET.
Step-by-step explanation:
The region of the cerebral cortex that is associated with understanding language and preventing the accidental use of profanity is the prefrontal cortex. This area of the brain is responsible for complex cognitive behavior, personality expression, decision making, and moderating social behavior, including the use of language. Studies using brain scans, such as positron emission tomography (PET), indicate that the prefrontal cortex is involved in tasks that require semantic processing, which includes language comprehension and production.