Communication development requires normal hearing ability. Children must hear the sounds of speech and attach meaning to the language around them in order to produce the same types of behaviours. Typical development covers a wide variety of behaviours. This variation depends upon how many words a child understands, whether he or she has had any medical problems, ear infections and many other factors. As children learn language, they are also developing speech sounds.
Some sounds are more difficult than others and appear later.
However, by the age of 4, a child's speech should be understandable and he or she should be using all speech sounds correctly by age 6. Stuttering is a problem that often begins during the pre school years. Others continue to stutter and begin to view speaking as a difficult, frustrating experience. Stuttering is characterized by repeating of the first sound of words, or showing tension or struggling when saying words.