It is an anime depicting interaction between humans and youkai. Besides the conversation between high school students, conversations with youkai who speaks in a bit old-fashioned way also appear.
The content of Japanese is mainly the conversation between high school students. In this anime, there are young people’s words and young girls’ words that real Japanese high school students speak. It is good for listening practice of reality high school students’ spoken words but it is better not to emulate their way of talking.
The main three characters all have the kanji “葉” (は, Leaf) in their name. The title: three leaves three colors is based on an idiom “Sansha-sanyo”, meaning everyone is unique.
There are elements like fantasy, including birds that speak human language, but there are many characters that speak natural ways that we hear on a daily basis. It is interesting to note that there are many character names related to mochi(rice cake).