Why are these questions important?

The language and communication behaviors exhibited by children from the very first moment of language acquisition provide important information as to whether the child shows a typical mental development. In addition, the language and cognitive abilities of the individual in early childhood provide clues about their development in primary education and onwards (e.g., skills related to reading, writing, expression, mathematics, and problem solving as well as social and communicative skills, etc.). Therefore, an important condition for understanding the mental development of children is to understand how their language skills develop.