Final answer:
The influence of his colleague's act had a breakthrough effect on Jean-François Champollion as the inscription, known as the Rosetta Stone, played a crucial role in deciphering hieroglyphics and unlocking the understanding of ancient Egyptian language and culture.
Step-by-step explanation:
The influence of his colleague's act of sending him a copy of an inscription found in the ruins of a temple on the Nile River island of Philae had a breakthrough effect on Jean-François Champollion. The inscription, known as the Rosetta Stone, played a crucial role in deciphering hieroglyphics and unlocking the understanding of ancient Egyptian language and culture. It enabled Champollion to realize that hieroglyphs recorded the sound of the Egyptian language, which significantly advanced his research and contributed to a growing knowledge of Egyptian society, history, and cultural changes.