**Core Concept**
The 12th cranial nerve, also known as the hypoglossal nerve, is responsible for controlling the movements of the tongue. Damage to this nerve can lead to various motor and sensory disturbances in the tongue.

**Why the Correct Answer is Right**
Right 12th nerve damage affects the motor innervation of the right half of the tongue, leading to weakness or paralysis of the affected side. This results in difficulty in protruding the tongue, swallowing, and articulation of speech sounds. The hypoglossal nerve is a motor nerve that supplies the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus muscle, which is innervated by the 10th cranial nerve (vagus nerve).

**Why Each Wrong Option is Incorrect**
**Option A:** This is not a known consequence of 12th nerve damage.
**Option B:** This is incorrect because 12th nerve damage does not typically affect the 9th cranial nerve (glossopharyngeal nerve), which is responsible for swallowing and taste.
**Option C:** This is not a direct consequence of 12th nerve damage.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of 12th nerve damage is difficulty in protruding the tongue to the affected side, which can be tested using the "tongue protrusion test".

**Correct Answer: D. Difficulty in protruding the tongue to the affected side and weakness of the right half of the tongue.**