So you use intonation like that a lot to show that you're excited about something, that you're happy about it, that you're talking, you're serious about something in a very, very high level way, which is very difficult to learn.
イントネーションは、自分が何かに興奮していること、喜んでいること、話していること、真剣に何かに取り組んでいることを表現するのに使うんだ。