Background: Speech and language disorders—particularly delayed speech and language development [DSL]—are not
uncommon for children with cleft lip and cleft palate [CLP]. If DSL is not treated in a timely and appropriate manner, it might affect the child’s communication, literacy, and education. The magnitude of DSL in children with CLP has not been formally studied in Thailand.
Objectives: To investigate the prevalence of DSL in children with CLP.
Materials and Methods: 397 children with CLP registered at the Srinagarind Hospital Speech Clinic between 2009 and 2014 were included in the retrospective study. The speech and language screenings were scored (pass = 0 and fail = 1) based on the normal level with Adapted Early Language Mile Stone for Thai Children; Thai speech and language test for children between 1 and 2 years of age; Thai speech and language norms for children 2 1/2 to 4 years of age; and Utah Test of Language Development. Speech and language errors were listed as a guideline for speech therapy planning.
Results: Prevalence of DSL in children with CLP ranged between 4.3 and 44.40% (average 18.70%; 95% confidence interval = 14.90, 22.90). The common item of speech and language errors was drawing or painting (100%), copying common words (75%), telling days of the week (50%), telling full names and surnames (28.57%). This information is useful for speech therapy planning and further speech and language promotion.
Conclusion: Prevalence of DSL was a common defect in children with CLP. Early diagnosis and early intervention are needed to facilitate good quality of development, learning, and life.

Keywords: Prevalence, Speech and language delay, Cleft lip, Cleft palate, Delay speech and language development