Celtic, Italic, Greek and several other IE languages have a P- and a Q-variety (from kw > p and gw > b). The P-variety usually also has h for ancient s. What would be the best linguistic term for describing this combined phenomenon? Labialization? Develarization? Lenition?
The change from
/h/ is called debuccalization, from Latin bucca, "mouth". The name is generally applied to any change that turns a non-glottal sound glottal, since it's moving the articulation "out of the mouth"; another example is English
The change from
/p/ doesn't have a universally-accepted name in my experience; I've seen it called both labialization and develarization (since the labiovelar consonant is losing its velar closure and becoming purely labial).
I'm not aware of any real correlation between the two sound changes; I know they both happened in some varieties of Greek, but initial
/h/ was universal in Hellenic, and
/p/ was less consistent;
/h/ didn't happen word-internally or finally, either. Similarly, Romanian had develarization, but not
/h/: consider Latin socium → Romanian soț, with the original
I am totally aware of all that has been replied, but my question was one of terminology, as there doesn't seem to be a generally agreed term. So, I was asking around. Until now, I have been using the term 'labialization', but that seems ambiguous because it is also used to describe adding a labial feature to velars.
The transition s > is not limited to Hellenic: it also happens in P-Celtic (sal > hal) and P-Italic. It is a frequent companion of the labialization/develarization (or whatever would be a better term). I just don't know why because they seem unrelated at first sight.
Both phenomena happened almost simultaneously in the three branches of IE in the period 1,200-800 BCE. My guess is that it happened in a presumed northern Balkan Sprachbund stretching from Hallstatt to Epirus or thereabout. Note that P-Italic clearly 'invaded' Italy from Dalmatia, leaving only a small area around Rome/Italian west coast with the older Q-Italic.(BTW. there is a present-day trans-branch Balkan Sprachbund, with Bulgarian/Macedonian (Slavic), Romanian (Italic)and Greek (Hellenic), so it is not unthinkable something similar existed in Antiquity).Research paper: https://www.academia.edu/9796216/Celtic_and_the_Adriatic_-_A_completely_reconsidered_view_of_Celtic_linguistic_prehistory_-_Updated_18.12.2018