By the time a child is 4½ years old most speech sounds are in place and the child is easily understood by the people with whom he/she communicates. 

Articulation difficulties are demonstrated when a child mispronounces individual sounds, such as “w” for “r” (“wed” for “red”) or lisping.

When children group sound errors into patterns that are incorrect, such as leaving off final sounds (“cu_” for “cup”), using sounds made in the front of the mouth rather than using sounds which are made in the back of the mouth (“tar” for “car”), not producing the whole word “bu-fly” for “butterfly”). 

This type of error is considered phonological and is treated differently from articulation disorders.

If a phonological disorder persists, the characteristics of apraxia of speech may be impacting the child’s progress. 

Other factors contributing to persistent speech production difficulties may include but are not limited to a history of chronic ear infections, oral-motor structures and functioning, tongue thrust.