A delay in the onset of speech in a child (language delay) may have many reasons. Parents should always remember that there is an enormous variation between children when learning to speak, and a delayed start to speech is not necessarily a sign of some serious condition. Nevertheless, if parents are concerned about a significant delay in their child’s language development, they should seek professional assistance.
Delayed speech may be due to deafness, a lack of stimulation (people not talking near them), an intellectual disability, autism and abnormalities of the mouth and throat (e.g. cleft palate).
Some children just decide that they do not want to speak, and then suddenly start speaking quite fluently at a later age.