They may be referring to hyperlexia (rather than hyperverbal ability):
Hyperlexic children are characterized by word-reading ability well
above what would be expected given their age. ... Some experts believe
that most children with hyperlexia, or perhaps even all of them, lie
on the autism spectrum.
But as far as verbal ability goes, since autism is a ...
What you propose
Is it possible that someone has level-3 (severe) autism yet on superficial look or talk the disability does not appear?
is nonsense by the usual (DSM) definition of autism, which is based on several criteria which are behaviorally defined, i.e. from an observer's standpoint, to start with
a child must have persistent deficits in each of ...
Yes, this may happen with Asperger subtype of autism.
AS had already been described in 1981 by Lorna Wing, who first
proposed the term to refer to a special subgroup of children who,
according to Asperger’s original description, were characterized by:
social isolation and lack of reciprocity in social interactions;
normal or precocious language acquisition, ...
There is an ongoing debate as to whether it is best to view personality disorders as being categorical or dimensional in nature. Your question infers the perspective of the categorical view. The alternative dimensional perspective suggests that the three disorders you mention are very similar, that is, these three conditions overlap to a large extent with a ...
There are several other aspects that I think are not just "perceptions" but something more complicated.
Having an weak or a different theory of mind; that hinders processing in general how other people may perceive or interpret something.
Having difficulty with cognitive empathy; that hinders understanding others' motives and intentions.