The author gothad become interested in decoding thea script on ancient architecture by learning Luwian, of which Ia language I have never heard thoughof.

"Got" is not a word that is used very often in written English. And it is "a" script, not "the" script because this is the first time it's being mentioned in your writing. Technically ending a sentence with "of" is grammatically incorrect but it sounds much more natural. Only very harsh teachers will say ending a sentence with "of" is wrong.

Though I'm gladhappy to read and correct articles written in Japanese, I want to know why those who live far from Japan gotbecame interested in Japanese.

I cannot explain why, but "happy" is more natural than "glad" in this circumstance. "Became" should be used in place of "got," "got" is a vague word.

I guess that anime and manga enticed them to learn the original language.

They are just killing the time, and besides, learning foreign languages helps you to get a new job.

The phrase "killing time" usually doesn't contain "the."

The author got interested in decoding the script on ancient architecture by learning Luwian, of which I never heard thoughthough I have never heard of that language.

I rephrased the ending of this sentence because it sounded a bit awkward, however it was still comprehensible.

I guess that anime and manga enticed them to learn the original language (they were made in).

I understood "original language" to mean the language the anime and manga were written in, however I felt that it might be a bit unclear, so I added the extra text.

I read an article sayingwhich said that people who gethave more free time due to the lockdown tend to start learning foreign languages.

They are just killing the time, and, besides, learning foreign languages helps you to get a new job.

The author got interested in decoding the script on ancient architecture by learning Luwian, a language of which I had never heard thoughbefore.