Final answer:
The hypoglossal nerve is responsible for tongue movement and is essential for speech, which evolved in humans around 500,000 years ago to allow complex communication, likely giving Homo sapiens an advantage over other hominins.
Step-by-step explanation:
The hypoglossal nerve, which is also known as the twelfth cranial nerve, is primarily responsible for the contraction of the muscles of the tongue, aiding in its movement. This nerve's functionality is crucial for several integral oral mechanisms such as mastication (chewing), deglutition (swallowing), and importantly, speech. An impairment in the hypoglossal nerve can result in difficulties with speech and swallowing, which are essential for communication and sustenance intake.
Importance of the Hypoglossal Nerve in Spoken Language
Complex speech patterns and sounds are facilitated by the tongue's versatility in movement, which the hypoglossal nerve enables. Researchers believe that the capability of producing a vast array of sounds through such movements was developed around 500,000 years ago, which coincides with the period when humans allegedly obtained a distinct vocal tract. This evolution in the vocal tract, including a descended larynx and a larger, rounded tongue, has been linked to the progression of the Homo species, enhancing communication and potentially contributing to the dominion of Homo sapiens over other hominins like Neanderthals.