Our guest is Thomas Sowell, author of a new book on the subject.
Many children talk late for a wide variety of reasons.
They may be mentally retarded, autistic, or have hearing problems. No one really knows, but there is a connection, that we know. More than half of the children have an engineer as a close relative, and four fifths have a close relative who plays a musical instruments. The children themselves tend to be very analytical and very musical. Among the famous people who have talked late were three nuclear physicists who worked together creating the first atomic bomb.