Editor's Note: Dr. Ellenmorris Tiegerman is the founder and executive director of the School for Language and Communication Development in Glen Cove.

When parents are concerned about their child's behavior, language and/or social skills, the first question they often ask is, "Is he or she normal?" The word "normal" is not a helpful term since typical or average behavior includes a range of functioning. Especially in urban communities where there is a mix of diverse cultural groups even the term "average" can be challenged.  

Be that as it may, there are two questions that parents can use that may provide more constructive information concerning their child's development. Firstly, does the child's behavior fall within a range of typical behaviors? Secondly, is the behavior developmentally appropriate given the child's age?  

The range of normal variation is very clear particularly in early language development. For example, Melissa may begin using words consistently at 8 months but Tanya may not until 18 months. This wide range can be very anxiety provoking for many parents when comparisons are being made on the play ground or at family gatherings. These developmental language variations have been documented in research studies highlighting variations in children's rate of acquisition as well as styles of children's early language.

Some children use an expressive style which consists of early words that are linked to social relationships rather than objects. These children learn pronouns such as "you and me" and social words such as "no, yes, want, please." This is in contrast to children who have a referential style of language acquisition. The early vocabulary for these children consists mainly of names for objects or people.

The point is that children develop differently all throughout their childhood and adolescence. How these language differences come about is not clear. There are theories related to environmental as well as hereditary factors.  

Whatever the explanation, however, the existence of such large differences in language, social and cognitive behaviors raises questions about the assumption that early development is the same for all children. If all children developed in the same way, then where do these stylistic and individual differences come from? The point for parents to understand is that variability and variation is a "normal" part of the developmental process.