I'm sorry to say that although you have kindly clarified the elements of
your argument, your reasoning process still does not establish that Pali was
the language spoken by the Buddha. It may or may not have been but you do
not really "know" either way.
Putting this into a Buddhist context, it is clear that you rely upon
scriptural authority, which is rightly rejected by all Buddhist pramanikas
after Dignaaga. Scriptures are not acceptable as a pramana in debate
precisely because there is no guarantee that their claims are true per se --
eg the Nikayas, the Bible and the Quran are contradictory in their claims.
To illustrate this, using your "reasoning", let me take a somewhat
provocative parallel argument (which is, of course, similarly invalid):
Mahayana is superior in all respects to Theravada (Sthaviravada)
How do I know this ?
Because it is stated by many Mahayana masters in Mahayana texts.
I believe them because I do not see any reason why they would tell lies.
Telling lies is against the Vinaya rules, and Mahayana masters followed the
Vinaya rules.
If your own argument is logically valid as it stands, then so is the above
claim. But as it is actually invalid, then so too is your argument.
Thus, there are only two valid sources of knowledge: A) direct perceptual
knowledge (pratyak.sa) and B) inferential knowledge (anumaana). It is
probable that you could only appeal to A) direct perceptual knowledge if you
were actually present at the time the Buddha spoke, which I doubt you would
claim. That leaves B) inference which requires proof (hetu), which you have
not provided. In fact, your argument is really based on at least two
unwarranted claims from belief, not factual and verifiable knowledge: i)
your belief that what the good monks wrote was true, because of ii) your
belief that they did not lie (also, note that they might not have
intentionally lied, but they might have been mistaken). You also provide no
verifiable proof for their being arhats so that argument is also invalid.
To prove your claims you will need to adduce corroborative *facts* which can
be validated independently. While I accept that you know what you have read,
you have not shown how you "know" what you have read to be true, apart from
an appeal to your "belief" that such is the case. Logically speaking, it is
obvious that your proof (= your belief) precedes your knowledge claim, and
therefore, although you have tried to deny this, your implicit sequence of
reasoning is indeed as I characterized it - based on belief not knowledge.
Indeed, to my mind, your argument suggests naive fundamentalism.
Now, if you would like to start again, could you present a rational argument
based on proof, and not dogmatic belief, for why Pali was definitely the
language the Buddha spoke ? Could you also give your account of the
philological significance of the Girnar Inscriptions and the presence of
"archaic Magadhisms" in the Pali texts ? I would also like to suggest that
you read some of the articles in "The Language of the Earliest Buddhist
Tradition" edited by Heinz Bechert (1980)and disprove with equal rigour the
premises and rationally argued conclusion found therein, namely, that Pali
was very unlikely to have been the language of the Buddha.
I also thank you for your kind mention of Robert Kirkpatrick. But sorry, I
must turn down your proxy invitation as I taught English in Japan myself for
10 years without any complaints. Moreover, I am confident that my command of
English is quite adequate since none of the editors of the ten + books and
numerous encyclopaedia articles I have written and published over the years
have ever voiced any concerns such as you raise.
Finally, I must draw the attention of others to your web-site which I am
sure they will find quite illuminating.