1. I like King Sejong because he made the Korean alphabet, Hangeul.
2. I like King Sejong because he created the Korean alphabet, Hangeul.
3. I like King Sejong because he invented the Korean alphabet, Hangeul.
[I used three kinds of verbs. Which one is suitable for the sentence? Are they all possible?]
All make good sense, yes. If I had to choose one, I'd choose 2, but really, all are fine.
They are all usable but 3. is probably the most detailed and creative verb.
All three sentences you provided are grammatically correct and convey the same meaning. However, there are subtle differences in the use of the verbs "made," "created," and "invented" that can affect the intended meaning.
1. "I like King Sejong because he made the Korean alphabet, Hangeul."
This implies that King Sejong physically constructed or assembled the Korean alphabet. While this may not be entirely accurate, it can be used to express appreciation for the effort and initiative he put into developing Hangeul.
2. "I like King Sejong because he created the Korean alphabet, Hangeul."
"Created" emphasizes King Sejong's role in bringing the Korean alphabet into existence. It suggests that he came up with the idea and implemented it, imparting a sense of originality and innovation.
3. "I like King Sejong because he invented the Korean alphabet, Hangeul."
This emphasizes King Sejong's ingenuity and implies that the Korean alphabet did not exist before him. It suggests that he conceived and developed the alphabet, attributing the new language system to his creative ability.
All three verbs are suitable for the sentences, but the choice depends on the specific meaning you wish to convey.