Awesome! Whoever thought of that deserves a free year's supply of cookies or something.

Let's pretend I did. Pay up.

Somebody with a speech impediment is going to be offended.

at some point many English speakers couldn't pronounce the letter R properly

The scientific method nearly 3000 years ago wasn't too bad, perhaps.

If your hypothesis relies on an undemonstrated premise to reach a conclusion, then that's pretty bad.

To say in hindsight that the premises or methods were wrong is science too.

All hypotheses do.

In what way is whether we are using scientific principles right now at all relevant to whether they were being fully employed in the case in question?

I hypothesize that you have no hair. That hypothesis does not seem to rely on any undemonstrated premise as a necessity for allowing a conclusion to be reached

But even the hypothesis itself can presuppose things, like on the philosophical level that solipsism is false.

The hypothesis also assumes that I am a living being capable of growing hair, not a computer program.

I don't believe that there is a nature given set of right scientific principles that we of the modern age finally have discovered independently.

Today's principles are built on the experience of former principles, and so will new principles of the future.

The premises or axioms that you need to conclude that Phrygians therefore were the first are most important, and it's already presupposed in the hypothesis itself, that there was a first man, that man isn't a result of evolution, a view that existed into the fairly recent history of science. Second, that language is congenital. Which might not be a silly assumption as it seems now if you already assume that man didn't evolve.