What does Luke 1:63 mean?
Zechariah is the father of Elizabeth's newborn boy (Luke 1:57), an event which was predicted by an angelic messenger (Luke 1:13). Zechariah was serving in the temple when the angel appeared to him (Luke 1:8–11). His first response to the prophecy was doubt (Luke 1:18), so he was temporarily rendered unable to speak (Luke 1:19–20).Being unable to speak—and possibly unable to hear (Luke 1:62)—does not mean Zechariah cannot communicate, at all. Hand signs and gestures can communicate some things. He's also capable of writing. The tablet mentioned here was a common object in that era. These were wooden or stone boards covered in a thin layer of wax. These were the ancient precursor to modern objects like dry-erase boards or chalkboards.
The reason Zechariah needs to write is because friends and family doubt Elizabeth's choice of a name for their son (Luke 1:59–61). "John" is the name the angel commanded, and "John" is the name Elizabeth chose. Most likely, she had been told about the angel's message by Zechariah. To settle the issue, those involved have asked Zechariah, and he produces exactly the name mentioned by Elizabeth.
This surprises those who see it, but their surprise will soon be multiplied. Confirming the name "John" completes the angel's prophecy about the birth, which also concludes Zechariah's term of silence. He will immediately begin to praise God and prophesy, greatly affecting those nearby (Luke 1:64–66).