You are actually teaching your child a second language during a time in his life when he is most receptive to language formation. There are some who desire to substitute the word childishness in place of foolishness. That is not possible. The original Hebrew language does not support it. There is a difference between foolishness and childishness.
Foolishness is a biblical anthropological description of a child's heart.
Childishness is not directly mentioned in the Bible, but is a description deduced from common study of childhood behavior. Childishness is associated with innocent immaturity, the honest mistakes children make. Foolishness needs correction but parents should not correct all foolish behavior the same way, or with the same consequence. Biblical discipline begins with parental instruction. When we consider the role of instruction in a child's life, there are a few facts and elementary principles that serve as a guide to success for all of your parenting years.