Childhood-Onset Fluency Disorder (Stuttering) 45
developmental pattern, which is reflected in the age norms of standardized tests. It is not
unusual for typically developing children to  use developmental processes for shortening
words and syllables as they are learning to talk, but their progression in mastering speech
sound production should result in mostly in telligible speech by age 3 years. Children with
speech sound disorder continue to use immature phonological simplification processes
past the age when most children can produce words clearly.
Most speech sounds should be produced cl early and most words should be pronounced
accurately according to age an d community norms by age 7 years. The most frequently mis-
articulated sounds also tend to be learned later, leading them to be called the “late eight” ( l, r,
s, z, th, ch, dzh, and zh). Misarticulation of an y of these sounds by it self could be considered
within normal limits up to age 8 years. When multiple sounds are involved, it may be appro-
priate to target some of those sounds as part of  a plan to improve intelligibility prior to the age
at which almost all children can produce them a ccurately. Lisping (i.e., misarticulating sibi-
lants) is particularly common and may involve fr ontal or lateral patterns of airstream direc-
tion. It may be associated with an ab normal tongue-thrust swallowing pattern.
Most children with speech sound disorder re spond well to treatment, and speech dif-
ficulties improve over time, and thus the diso rder may not be lifelong. However, when a
language disorder is also present, the spee ch disorder has a poorer prognosis and may be
associated with specific learning disorders.
Differential Diagnosis