After watching the final scene of Satoshi and Pikachu's journey and hearing Type: Wild, I prefer the Japanese music for a few reasons. The first one being that I like how the majority of the themes are sung by Rika Matsumoto. It really makes it seem like it's Satoshi himself singing, and we're getting his feelings about all the adventures that he's going on.
Same with the other characters. Nyarth no Uta is still one of my favorite songs. Listeners can get a good sense of a different side of who he is that isn't really seen in the show.
The music also seems to emotionally hit better. While the English version is good, Chiisaki Mono just sounds more emotional and powerful to me.
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