S. [bm], [dn] became [mm], [nn]; [bm|dn] > [mm|nn]

Reference ✧ VT42/26

Related

Phonetic Rule Elements

[bm] > [mm] ✧ VT42/26.0503 (bm > mm)
[dn] > [nn] ✧ VT42/26.0412 (dn > nn)

ON. voiced stops became nasals before nasals; [{bdg}{mn}] > [{mnŋ}{mn}]

This sound change was described by David Salo (GS/§4.47) and can be deduced from the examples in the Etymologies. The clearest examples of this change are:

In the second example, ON. yadme is attested as an element in ON. elyadme “sky-bridge” = “rainbow” (Ety/ƷEL) and its later form ON. *yanme is attested in the plural: yanmī “bridges” (PE22/27). @@@ Later changed to only homorganic stops (VT42/26)

References ✧ PE22/26, 35

Variations

Phonetic Rule Elements

[bm] > [mm]
[bn] > [mn]
[dm] > [nm]
[dn] > [nn]
[gm] > [ŋm]
[gn] > [ŋn]

Phonetic Rule Examples

dubna > dumna bn > mn ᴹ√DUB > N. dofn ✧ Ety/DUB.023
kelebna > kelemna bn > mn ᴹ√KYÉLEP > celefn > N. celevon ✧ Ety/KYELEP.053
lebna > lemna bn > mn ᴹ✶lebnā > N. lhevon ✧ Ety/LEB.021
sθabne > sθamne bn > mn ᴹ✶stabnē > ON. sthamne ✧ Ety/STAB.013
tubna > tumna bn > mn ᴹ✶tubnā > N. tofn ✧ Ety/TUB.031
eljadme > eljanme dm > nm ON. elyadme > N. eilian(w) ✧ Ety/ƷEL.051
jadme > janme dm > nm ᴹ✶yatmā > N. ianw ✧ Ety/YAT.017
madna > manna dn > nn ᴹ✶matna > N. mann ✧ EtyAC/MAT.017
padna > panna dn > nn ᴹ✶patnā > N. pann ✧ Ety/PAT.029
padna- > panna- dn > nn ᴹ√PAT > N. panno ✧ Ety/PAT.025
dogme > doŋme gm > ŋm ᴹ√DOƷ/DÔ > dogme > dongme > ON. doume ✧ Ety/DOƷ.016
nagma > naŋma gm > ŋm ᴹ✶nakma > N. naew ✧ Ety/NAK.023
ragme > raŋme gm > ŋm ON. ragme > N. rhaew ✧ Ety/RAK.030
sagma > saŋma gm > ŋm ᴹ✶sagmā > N. saew ✧ Ety/SAG.013
sagma > saŋma gm > ŋm ON. sagma > saʒmh > sae̯mh > N. saęw ✧ PE22/032.2716
tagma > taŋma gm > ŋm ᴹ✶takmā > N. taew ✧ Ety/TAK.073
tegma > teŋma gm > ŋm ON. tegma > teiw > N. tew ✧ PE22/031.2410
tegme > teŋme gm > ŋm ᴹ✶tekmē > N. tîw ✧ Ety/TEK.050
kugna > kuŋna gn > ŋn ᴹ✶kuʒnā > N. cûn ✧ Ety/KUƷ.020
legna > leŋna gn > ŋn ᴹ√LEK > lhein > N. lhain ✧ Ety/LEK.008
lugne > luŋne gn > ŋn ᴹ✶lugni > N. lhûn ✧ Ety/LUG².007
magna > maŋna gn > ŋn ON. magna > N. maen ✧ Ety/MAƷ|MAG.022
ndagno > ndaŋno gn > ŋn ON. ndagno > N. daen ✧ Ety/NDAK.021
ragna > raŋna gn > ŋn ON. ragna > N. rhaen ✧ Ety/RAG.007
ragna > raŋna gn > ŋn ᴹ√RAG > N. rhaen ✧ EtyAC/REG.020
regna > reŋna gn > ŋn ᴹ√REG > rhein > N. rhain ✧ Ety/REG.008
rigna > riŋna gn > ŋn ᴹ√RIG > N. rhîn ✧ Ety/RIG.026
tagna > taŋna gn > ŋn ᴹ✶taʒna > N. taen ✧ Ety/TĀ.235