The factors causing delay on speech and language development were statistically studied. Subjects were 380 children who were diagnosed as “delayed speech and language development” at our clinic from 1977 to 1990. None of these children had moderate or severe hearing loss.
First, possible causal factors were pointed out. Then subjects were devided into groups according to the factors. Finally the capability of daily conversation at one's last interview was judged by using four step scale. The relations between each factor group and daily conversation ability were discussed.
The findings were as follows:
1. Mental deficiency was seen in 43% of the subjects. The capability of daily conversation varied among children with mental deficiency.
2. A group of young children who had no or little speech but did not have any apparent causal factors became capable of having daily conversation.
3. Children whose IQ were between 75 to 90 and/or who showed fine motor disfunction also became capable of having daily conversation.