A problem with fast-mapping a word is that
the child forgets most words learned this way.
when words are learned this way, good grammar is lost.
the child may misuse the word.
it interferes with other aspects of cognitive development.
Question 2
Because of fast mapping, a preschooler
needs several experiences with a word to learn it.
grasps the meaning of words describing emotions.
has a clear understanding of all the words he uses.
learns some words after a single exposure to them.