Isekai no Mahou Gengo Ga Doumitemo Nihongo Dattaken

One day due to an accident, Okata Kazuhiko, a university student living in Japan, drew closed the curtains on his short life. In the world he reincarnated as Gerald, he discovered that, for whatever reason, the language of magic was Japanese. Gerald, who had retained his memory, quickly grasped any spells due to his mastery of Japanese. Taking advantage of his unparalleled skill in Japanese, Gerald leaves his village in order to become the greatest magician the world has ever seen.