Final answer:
The event that caused God to splinter human language into many tongues is the Tower of Babel.
Step-by-step explanation:
The event that caused God to splinter human language into many tongues is known as the Tower of Babel. According to the biblical story found in the Book of Genesis, humans united to build a tower that reached the heavens. In response to their arrogance, God confounded their language, causing them to speak different languages.
This event is seen as a way to explain the diversity of languages in the world today.