OS. medial [s] assimilated to following nasal; [-{sm|sn}-] > [-{mm|nn}-]

OS. medial [s] assimilated to following nasal; [-{sm|sn}-] > [-{mm|nn}-]

In the (Old) Noldorin of the 1930s, it seems that primitive [s] in combination with a nasals [m] or [n] developed into [mm] or [nn]. There are several examples in The Etymologies:

Tolkien also alludes to the sound change sm, sn > mm, nn in his discussion of the Noldorin use of the Feanorian Alphabet from the 1930s:

In later Gondolic (after Y.S. 300) medial mb > mm. The letter t thus became used = [mm] of any origin (PQ pm, bm, sm, mm, mb) and is usually transcribed mm ... In post-Exilic, Toleressean, [mm] generally > [m] but this was not recognized usually in spelling ... In late Exilic (after Y.S. 307) [nd] > [nn]. The letter 5 thus became used of [nn] of any origin (PQ tn, dn, sn, nn, nd); and is usually transcribed nn, except in ancient historical Gondolic names: as Gondolin (PE22/35).

David Salo noted this development, theorizing the medial sound changes resembled the corresponding initial developments, with the s first unvoicing the nasal and then assimilating to it with later revoicing (GS/§4.70): [-sm-] > [-sm̥-] > [-m̥m̥-] > [-mm-]. The above example ᴹ✶kas-ma > kazma > ON. kama “helmet” (EtyAC/KAS) hints at another path for the medial development, with the s voicing to z and then assimilating to the voiced nasal: [-sm-] > [-zm-] > [-mm-]. Tolkien mentioned such voicings of s did not happen in Primitive Elvish but were possible in Eldarin child languages, though he did not say specifically whether it occurred in Noldorin:

s became voiced whenever, by suffixion or abnormal vocalization of bases (see above), it came to stand before a voiced stop: thus sb, sd, sg > zb, zd, zg. Of these, only zd could be produced by suffixion; s was not voiced before other voiced consonants (as m, n, l, r, w, y) in Quendian or [Common] Eldarin, though voicing occurred in such positions in some of the individual languages (first version of Tengwesta Qenderinwa [TQ1], 1930s, PE18/54).

Similar sound changes happened in Welsh, where such s-assimilation occurred before both nasals and liquids: -sm-, -sn-, -sl-, -sr- > -mm-, -nn-, -ll-, -rr- (WGHC/§95ii). There is one example that hints that in Old Noldorin, -sr- might also become -rr-:

This does not seem to be the case in Sindarin, however:

There are similar examples where [-sr-] > [-θr-] in Noldorin:

For lhathron, it seems the consonant cluster was [-nsr-] in the Old Noldorin period, and only became [-sr-] later after nasals vanished before spirantal clusters. The Old Noldorin cluster was probably [-str-] in the other two examples: *lost-ren > *lhosren > lhothren and *ost-rond > *osrond > othrond. Thus, it’s possible that [-sr-] > [-r̥r̥-] > [-rr-] was the Old Noldorin sound change and [-sr-] > [-θr-] was the later Noldorin sound change after consonants were lost in larger clusters.

Conceptual Development: There are not many attested examples of these sound combinations in earlier iterations of the language, but it seems that in Gnomish at least the medial [sm] had the same development as initially, to [f]:

As noted above, it seems unlikely that medial sr > rr in Old Sindarin, but it is possible that sm, sn > mm, nn, since a similar change happened in Welsh. There is no clear evidence either way.

Related

Phonetic Rule Elements

[-{sm|sn}-] > [-{mm|nn}-]

ON. medial [s] assimilated to following nasal or liquid; [-V{sm|sn|sl|sr}-] > [-V{mm|nn|ll|rr}-]

References ✧ PE22/35

Order (04000)

After 02400 long final vowels were shortened ᴹ✶gaisrā > gǣsra > ON. gērrha Ety/GÁYAS

Related

Phonetic Rule Elements

[-sm-] > [-mm-]
[-sn-] > [-nn-]
[-sr-] > [-rr-]

Phonetic Rule Examples

asmale > ammale -sm- > -mm- ᴹ✶asmalē > ON. ammale ✧ Ety/SMAL
asmalinde > ammalinde -sm- > -mm- ᴹ✶asmalindē̆ > ON. ammalinde ✧ Ety/SMAL
kasma > kamma -sm- > -mm- ᴹ✶kas-ma > kazma > ON. kama ✧ EtyAC/KAS
besno > benno -sn- > -nn- ᴹ✶besnō > ON. benno ✧ Ety/BES
xerbesno > xerbenno -sn- > -nn- ᴹ√KHER > N. hervenn ✧ Ety/KHER
gę̄sra > gę̄rra -sr- > -rr- ᴹ✶gaisrā > gǣsra > ON. gērrha ✧ Ety/GÁYAS