He was a polymath, meaning he had a wide range of knowledge and skills in different areas, including:
* Medicine: He was a doctor.
* Literature: He wrote novels, poems, and essays.
* History: He studied and documented Philippine history.
* Linguistics: He studied languages and wrote in both Spanish and Tagalog.
* Art: He was a talented painter and sculptor.
While his knowledge of language is evident in his writings, he is not specifically remembered for his grammar skills.
It's possible you may be confusing him with another figure or misremembering a specific detail. If you can provide more context or information about what you've heard, I might be able to clarify further.