* He was a precocious child: Rizal's family emphasized education, and he was known for being very bright and quick-witted.
* He learned at home: In those times, many children learned the alphabet at home before attending formal schooling.
* He started formal education at age 3: Rizal began his formal education at the age of three, first with his mother, then with a private tutor, and later at a local school.
Therefore, it's likely that Rizal learned the alphabet around the age of 3 or 4 during his early home education.
It's worth noting that this is a reasonable estimate based on historical context, but there is no definitive record of when Rizal learned the alphabet.