ASL sign for: language delay

Language acquisition in which children are learning to talk (either vocally or manually) at a late time of life or at a much slower rate than other children.

"The most serious issue in the Deaf community is language deprivation among Deaf children, which is caused by the refusal of teachers, administrators, audiologists, and other "experts" to recognize the crucial importance of American Sign Language to our linguistic, cognitive, academic, and social health." -- Matthew S. Moore, 2016.

Hmm, no words found now but, hey, it doesn't mean there is no expression for this concept in ASL.