A lesion in the hypoglossal nerve (CN XII) would likely affect which function?

The hypoglossal nerve (CN XII) is primarily responsible for controlling the movements of the tongue, which are essential for various functions such as speaking, swallowing, and manipulating food within the mouth. A lesion in this nerve would result in weakness or paralysis of the tongue muscles on the affected side, leading to difficulties in tongue movement and strength. This impairment can significantly impact speech articulation and the ability to swallow efficiently because the tongue plays a crucial role in these activities.

The other options pertain to functions controlled by different cranial nerves. Vision clarity is associated with the optic nerve (CN II), facial sensation is governed by the trigeminal nerve (CN V), and hearing ability is linked to the vestibulocochlear nerve (CN VIII). Therefore, the impact of a lesion in the hypoglossal nerve is specifically tied to the motor control of the tongue, making the option regarding tongue movement and strength the correct choice.