Speech Pathologist Question:

Articulation disorder: It is a disorder caused due to difficulties producing or pronouncing sounds, and the sounds may be added, substituted, omitted, added or deleted by other words. For example, school becomes cool, and spoon becomes thpoon
Phonological disorder: Phonological disorder is usually seen in children altering the structure of words or change in the sound pattern like "do" for "go" and "tup" for "cup".