There are at least a few terms used to describe specific speech impediments which are themselves difficult for a person with said speech impediment to say. For example:
Lisp: Frequently conceived of as causing a person to pronounce the letter "s" as "th", although other forms of the condition exist.
Rhotacism: Inability to pronounce the letter "r".
Blaesitas: Softening hard consonants and hardening soft consonants; including the pronunciation of "b" as "v" or "p".
Are there more examples like this?
Was this a deliberate choice (presumably related to alliteration), or is it merely coincidental? I'm sure doctors wouldn't have chosen these words specifically because the affected people can't pronounce them, but is there an explanation of why these terms in particular were adopted?