Hey guys! Long time no see. My Bachelor thesis was eating a lot of time, combined with work on the Greek Etymological Dictionary and me just simply enjoying my holiday. But I'm back, with this word that has been bothering me for some time now.
The word Skt. sthā- 'to stand', is besides its double representation of the Laryngeal quite straightforward. Now if we look at its causative though, something really funny happens. Usually a causative is formed by giving the root lengthened grade (from PIE *o in open syllables) and adding the suffix -aya-. Words ending in vowels though would get the situation where we'd have **sthā-aya-. which is a rather unfortunate cluster of vowels. To remedy this, Sanskrit puts a -p- between the root and the suffix resulting in sthāpaya- 'to cause to stand; to stop'.
Why a p? This is not at all a natural transitional consonant you'd put there. A y would be a lot more likely (and quite common practice in Sanskrit). Since it can not be readily understood by phonetic reasons, there's two more examples. The Vedic people were feeling funny, and thought it'd be nice to come up with a completely nonsensical transition sound, or it is archaic.
As a historical linguist, I feel compelled to further research the archaic option. Indo-European has certain elements behind certain stems called 'stem-extension'. These are always simple consonants like *k, *p or *u. The function of these stem-extensions have always been a bit mysterious. A nice example is the root *(s)ker- ''to cut' as found in Dutch scheren 'to shave' beside *(s)ker-p- which we find in Old English sceorfan 'to bite'.
I believe that this p that shows up in Sanskrit might give us an indication of the original function of the *p-stem-extension. Maybe originally this was a way to form causatives from verbal stems, which was later replaced by the common textbook causative formation. A nice note to put with this is, that Anatolian indeed is unfamiliar with the textbook causative formation, so there's some indication that it's recent.
While most p-causatives in Vedic Sanskrit occur after Laryngeal final roots, there are a few verbs that show this p even without them ending in a vowel/laryngeal. These are r̥- 'to go'; ar-p-áya- 'cause to go' and kṣi- 'to dwell' kṣe-p-áya- 'cause to dwell'.
All in old, Sanskrit seems to give a strong indication that the *p-stem extension is an old causative formation. Now we must look to see if there's any other words out there in other languages that seem to support this idea. Germanic *(s)ker- 'to shave/cut'' ~ *(s)ker-p- 'to bite' might be seen as a reflex of this, though the difference is rather more intensive than causative.
There is lots more to say about these stem extensions, and I'm nowhere near done figuring them out. There's some really odd stuff going on with the voice of these extensions for example. They seem to become pre-glottalised sometimes for no apparent reason.
As a final little side-note sthāpaya- looks suprisingly much like the Dutch verb stoppen 'to stop'. I don't buy the commonly cited Latin etymology stupere (it wouldn't explain with Dutch and Enlish both have the vowel o rather than u, or English with u and Dutch with o), it can hardly be cognate either, since the vowels would be wrong, and Dutch p points to PIE *b, which is very odd to have in the first place. So until I make any significant breakthrough on this bizarre word (which even if it is from Latin has a difficult reconstruction), I'll consider it completely unrelated.