This chapter examines speech sound difficulties and their phonetic, prosodic and phonological aspects. DSM-5 (American Psychiatric Association) specifies four diagnostic criteria for speech sound disorder. There is a persistent difficulty with the production of speech sounds which interferes with speech intelligibility or prevents verbal communication of messages (Criteria A). The disorder causes limitations in effective communication. These interfere with one or several of social participation, academic achievement or occupational performance (Criteria B). The symptoms first start in the early developmental period (C). The difficulties are not attributable to conditions existing at birth or acquired later, for example traumatic brain injury (D). Phonetics refers to the study of articulation, which is mastery of the sounds of the language. Phonetic aspects of speech include the speech sounds that are divisible into components of their articulation and into consonants and vowels. Prosody refers to speech volume, patterns of intonation and changes in pitch.