The origin goes back to common Indo-european roots.I'm subscribing because I would like to know too.
The following may be related, may not be:
KN of know is there because of the Greek or Roman roots of the word. Greek "gnosis" .. and I'm not sure what the Latin is, but we see it's descendents "conocer" and "conoscere" (Sp. & It.). My guess is that when this word first came into English, the K was pronounced... have no idea when it dropped out though. I believe knee reflects probably the same phenomenon, but that is pure conjecture.
Exactly when did the "k" in "kn" words like "knee", "knead" etc. become silent?
Alas, the paper doesn't give more information on the play (or poem). Maybe this one.Shakespeare did make a pun relating “knight” to “night,” which strongly suggests that it may have been silent by his time.
It could also be a matter of analogy.The Bloomsbury Dictionary of Word Origins records that 'knickers' was coined as a word in 1882. A writer in the magazine Queen in 1882 wrote 'flannel knickers in preference to flannel petticoat'.
I would hazzard a weak guess that the k may have been pronounced at that time or the spelling may have been changed with the introduction of the new word.
In English, the k is now silent, alike in educated speech and in most of the dialects; but it was pronounced apparently till about middle of the 17th c. In the later 17th and early 18th c., writers on pronunciation give the value of the combination as = hn, tn, dn or simple n.
Groetjes,reduced in standard Eng. to n, which was finally established XVIII, though current earlier.