PTCh evolved from PTH, the soft Heh moved slightly forward and
became more course. PTH also means to open, but in context it is
more often than not a behavioral open than a physical:
This can certainly explain how PTCH developed from PTH, and PQCH
developed from PQH.
> The similarities between the two are a case of CONVERGENT
EVOLUTION found in language and nothing more.
Could be but, imho, your conclusion is highly assumptive.
In fact, in retrospect I don't think one can summarily dismiss the
possibility that the concept of opening in these verbs was originally
inchoate in the scribal practice of using a circle as a logogram to
represent the opening that Hebrew wordsmiths called peh, considering
that 1) the letter peh was by all accounts originally nothing but a
circle, and 2) words for mouths, per se, were derived from words that
referred more broadly to openings.
In other words, in view of the acrophonic practice, whereby ancient
scribes derived prototypal letters from logograms representing
monosyllabic words, it is very possible that the abovementioned
logogram came down through history as 1) the letter peh, and as
2) peh differentially vowelized as the first syllable in these and
other ancient Near Eastern words for openings.