Error patterns in these children are produced in a constant manner with specific errors. The performance of these children is poor in phonological awareness, trans linguistic and reading and writing tasks. Children with stable phonological disorders perform normally in oral motor tasks and speech motor planning. Children who show such errors have language-cognitive defects in linguistic rules. It may be difficult for children to learn to pronounce words correctly. This is actually a part of their growth process. Over time, their speaking skills gradually improve. Children at any age master certain words. Most children at the age of 8 can pronounce all the sounds of different letters well and correctly. But some children have problems in pronouncing the sounds of letters and words. This means that they are unable to pronounce some sounds and words that should be pronounced without problems at their age. This disorder makes it difficult for the child to understand the lessons. Disturbance in pronouncing sounds includes the child's "Phoneme expression disorder" and "Problem in phonological process": Phoneme expression disorder: In this type of speech disorder, it is difficult for the child to pronounce some sounds correctly. For example, pronunciation of phonemes that requires special movements of the tongue in the mouth. Like the vowels "L" and "R" are difficult for him. Disturbance in the phonological process: A child with this type of speech disorder has wrong repetitions in pronouncing words. For example, he does not pronounce some phonemes of a word.