Which animation?

Four pairs of bright eyes are shining red, yellow, blue and green. These are four lively and lovely elves. They jumped into the drift bottle and braved the wind and waves to come to earth. Their only wish is to know more about the world and hope to become human girls one day. Because I know little about world common sense, I have held a training class at my teacher's house for one year. After a series of happy, interesting and horrible adventures, this lovely and funny animation has just been released in Japan. Because the four protagonists know nothing about human beings, they communicate, learn and make progress in the simplest language. Joining them can not only learn the purest and lovely Kawaii Japanese accent, but also learn about Japanese solar terms and human feelings step by step in 12 months, which is definitely worth it.