Although young children do not typically produce their first words until the 2nd year of life, the findings reviewed above make it clear that by the end of their 1st year, children know a great deal about the language spoken around them. Evidence of this sort is sobering for those of us who are responsible for the identification of communicative problems in children. Each month that passes in the child's 1st year could well represent a possible opportunity to remove or apply some external factor, or to foster some compensatory skill. However, from another standpoint these data should be welcome, for they serve as a powerful justification for advocating early intervention.