"Language deprivation is the term used for when a child does not have access to a naturally occurring language during their critical language-learning years. Language and cognition are so intertwined when a child is deprived of a first language (L1) during their critical period. The resulting deficits include significant delays in cognitive and linguistic functions. Fortunately, language deprivation in a Deaf child has a known cause and a cure. The cure is early and robust access to a signed language. Signed languages are the only languages that are 100% accessible to a Deaf child."
 
Kimberly Sanzo, MS, CCC-SLP via Therapy Travelers