Causes of Speech and Language disorders:
Speech and Language disorder may be caused because of absence of proper biological prerequisites or may exist because of other disorders and disabilities like ASD, ADHD etc.
Biological Prerequisites include Apparatus of the following System:
- Regulatory System – Brain, Nerves, Spinal Cord
- Auditory System – Ear , Auditory Cortex
- Articulatory System – Tooth, Tongue, Lips
- Phonetary System – Larynx, Vocal Cord
- Respiratory System – Nose, Lungs
Any malfunction, lesion in any of the apparatus or structural defeat in any of the organ cause Speech and Language disorder.
Common reasons of speech and language disorders include hearing loss, neurological disorders, brain injury, intellectual disabilities, drug abuse, physical impairments such as cleft lip or palate, vocal abuse.
According to ASHA,
The case of Speech and Language impairment, the causes are difficult to determine. However a number of factors have been proposed, including cognitive processing deficits (e.g., Miller, Kail, Leonard, & Tomblin, 2001; Ellis Weismer & Evans, 2002; Leonard et al., 2007), biological differences (e.g., Ellis Weismer, Plante, Jones, & Tomblin, 2005; Galaburda, 1989; Hugdahl et al., 2004), and genetic variations (e.g., Rice, 2012, 2013). These factors may not be independent of one another. For example, a genetic variation might lead to a difference in brain morphology or function that leads to a difference in cognitive processing.