Box 1.

Causes of delayed speech and language development and red flags.[5]

Causes of delayed speech and language development

1. Hearing impairment

2. Perinatal risk factors resulting in hearing impairment

3. Disorders of central nervous system processing:

(a) Global developmental delay

(b) Intellectual disability

(c) Autism spectrum disorder

4. Developmental language disorders

5. Disorders of speech production:

(a) Articulation disorder

(b) Dysarthria

(c) Verbal apraxia

6. Presence of anatomic abnormalities (e.g. cleft lip, cleft palate)

7. Environmental deprivation

Red flags in speech and language development

1. Inconsistent or lack of response to auditory stimuli at any age

2. Regression in language or social skills at any age

3. No babbling by age 9 months

4. No pointing or gesturing by age 12 months

5. No intelligible single words by age 16 months

6. No joint attention (i.e. following the eye gaze of others) by age 15 months

7. No two-word spontaneous phrases by age 24 months

8. Inability to respond to simple directions or commands (e.g. ‘sit down’, ‘come here’) by age 24 months

9. Speech predominantly unintelligible at age 36 months

10. Hypernasality at any age

11. Inappropriate vocal quality, pitch or intensity at any age