Calling it concatenation is a little misleading.

Japanese is known as an agglutinative language [0], and how verbs are conjugated also has a lot to do with politeness, as well as local dialects. That's why you can turn on an anime and hardly understand it, even after a couple years of study.

I got to the third year college level in my own Japanese studies, and at that point, memorizing kanji was starting to compete with my computer science studies, so I had to drop it. I got to travel to Japan and live with host families (we kind of settled on a Japanese/English pidgin), so I don't regret the experience.

[0] https://en.wikipedia.org/wiki/Agglutinative_language