Correct me if I'm wrong:
For those wondering what this is about. The girl is doing vocal practice in front of the mirror by making
use of the poem "Song of the Water Strider" by Hakushu Kitahara. People use this to practice their Japanese.
Explanation of the sentences:
A water strider is red A-I-U-E-O
(Amenbo Akai Na A-I-U-E-O)
Persimmon Tree, Chestnut Tree, Ka-Ki-Ku-Ke-Ko
(Kaki No Ki Kuri No Ki Ka-Ki-Ku-Ke-Ko)