*-men- stems in PIE and Germanic (1)

It's a fairly complex issue, so I'll divide it into a few sections
posted separately, for the sake of clarity. I'll try to present the
current mainstream opinion, avoiding personal speculation whenever possible.

The most primitive formation containing the derivational morpheme *-men-
are deverbal neuters (nomina rei actae), highly productive in the
protolanguage (more so, at any rate, than similar and functionally
related formations, such as heteroclitic neuters in *-wr./*-wen-). The
dominant and best evidenced type is proterokinetic:

nom./acc.sg. *R(é)-mn.
gen.sg. *R(z)-mén-s

R(z) = the zero grade of the root

The collective was originally of the shape *R(z)-mé:n (from earlier
*-mén-h2). On the analogy of acrostatic neuters the *-men- stems
developed a new type of collective, *R(é)-mo:(n), with amphikinetic
inflections (the weak stem was *R(z)-mn-'). Both types of collective
gave rise to animatised derivatives (masculine or feminine in Core IE),
represented by *bHudH-mé:n and *h2ák^-mo:(n), respectively.

Already in PIE, the accented instrumental ending *-éh1 was generalised
for all types of ablauting stems, so even a proterokinetic noun like
*kWér-mn. 'thing done' (Ved. kárman-), gen. *kWr.-mén-s, had the
inst.sg. *kWr.-mn-éh1. It seems that the nasal cluster was simplified at
a very early date, before the development of syllabic resonants in PIE:
*-mn-éh1 > *-n-éh1. The same simplification is attested in the
declension of animate nouns in *-men- and *-mon-: gen.sg. *h2(a)k^-n-és,
inst.sg. *h2(a)k^-n-éh1. Such case forms, while resulting from a regular
phonetic change, were morphologically irregular, so analogical repair
processes tended to remove them from post-PIE paradigms. They are,
however, attested directly in Indo-Iranian and less directly elsewhere
(also in Germanic, as will be seen).

*-men- stems formed thematic derivatives with accented *-ó- suffixed to
the zero grade of the suffix (more complex derivatives will be ignored
for now). As before accented inflectional ending, the suffix underwent
phonetic simplification. Since derived thematics were more independent
of their historical bases, analogical reshaping was less common in their
case (though it certainly took place from time to time). Nevertheless,
since the process of thematicisation remained productive, new
(late/post-PIE) instances of *-m(e)n- + *-ó- did not follow the old
phonetic rule, ending up as *-m.n-ó-.

It's possible (but not universally agreed) that the result of the
simplification of *-mn- could be *-m- as well, perhaps depending on the
place of articulation of the root consonants. Since this is a
controversial point, I will not develop it here.

(to be ctd.)

Piotr