Left: word 讠/言 (sound waves out of a mouth 口), right: stomach 胃 (...from the field 田 into this body part 月/肉), here: 田 as mouth with teeth The words come from the mouth-like 田 body part 月 when: speaking.
The app has many other functions, such as character selection according to difficulty, practice programs, handwriting recognition and success statistics!