in DSM–IV–TR, a communication disorder characterized by failure to develop and consistently use speech sounds that are appropriate for the child’s age.

n. a disturbance in the normal fluency and time sequencing of speech. It is characterized by frequent repetition or prolongation of sounds, syllables, or words, with hesitations and pauses that disrupt speech. 

in DSM–IV–TR, prominent hallucinations or delusions due to the direct physiological effects of a substance and not arising as part of a withdrawal syndrome.