Speech therapy pathology involves an evaluation to determine the source of incorrect speech patterns. For example, many speech impediments involve problems with articulation.
A speech therapist will perform an evaluation in order to determine the problem with the speech and isolate the troubled sounds.
When a speech pathologist offers an evaluation he or she records the troubled sounds and develops a therapy schedule to correct the unclear speech patterns.
Usually they perform therapy on one sound at a time. The most problematic sound goes first until the sound is mastered.
A common sound that many children and adults have problems with is the S sound. The S sound is formed when the teeth are clenched, but people that form this sound incorrectly often let their tongue protrude outward and form a TH sound instead.
When they make the S sound they form a lisp that makes the word inaudible. For example, the word snake would sound like thnake.
Most children master the S sound by the age of 9. Proper mouth and tongue formations are necessary in order to correct improper speech. This is really the key to language speech pathology.