<unk>  is a subset of autism where the person does not learn how to speak. It is estimated that 25% to 50% of children diagnosed with autism spectrum disorder (ASD) never develop spoken language beyond a few words or utterances.
Nonverbal autism
Selective mutism
High-functioning autism
Low-functioning autism
Autism spectrum
Developmental verbal dyspraxia
Mixed receptive-expressive language disorder
Tardive dysmentia