OS. initial [ml], [mr] became [bl], [br]; [m{lr}-] > [b{lr}-]

OS. initial [ml], [mr] became [bl], [br]; [m{lr}-] > [b{lr}-]

In Noldorin and Gnomish there are a number of examples of initial mr- becoming br-; this sound change must have occurred after unstressed initial syllables reduced to favored clusters. This same sound change occurs in the history of Welsh, sometime between Proto-Keltic and Britannic (WGHC/§99ii). Some Gnomish and Noldorin examples:

In Welsh there was a related sound change where ml- became bl- (WGHC/§99ii) and there are examples of this phonetic development as well in Gnomish and Early Noldorin (but no examples after the 1920s):

In Early Noldorin and Gnomish, there are further examples of dental nasal [n] becoming [d] before [r], [l]:

For the last example, bear in mind that [dl] became [gl] in Gnomish, as described by Roman Rausch in his Historical Phonology of Goldogrin (HSG/§2.4). He also identified the above sound changes in Gnomish, where initial nasals [n], [m] becoming stops before [r], [l] (HSG/§2.1).

Neo-Sindarin: There is no evidence of any of the above changes in Sindarin in the 1950s and 60s. Since mr-/ml- > br-/bl- in Welsh, Tolkien might have allowed these changes in Sindarin as well, and I include them in my phonetic rules for Neo-Sindarin. The nr-/nl- > dr-/dl- changes seem more dubious to me, but still possible. David Salo attributed the mr- > br- change (but excluded the ml- change) to Old Sindarin in Gateway to Sindarin (GS/§4.36). Salo also included ŋl- > gl-, but I can find no evidence of this and I don’t know where he got it from.

Phonetic Rule Elements

[ml-] > [bl-]
[mr-] > [br-]

ON. initial [ml], [mr] became [bl], [br]; [m{lr}-] > [b{lr}-]

Phonetic Rule Elements

[ml-] > [bl-]
[mr-] > [br-]

Phonetic Rule Examples

mrekāla > brekāla mr- > br- ᴹ√MERÉK > N. bregol ✧ Ety/MERÉK
mrekete > brekete mr- > br- ᴹ√MERÉK > N. breged ✧ EtyAC/MERÉK
mrekjā > brekjā mr- > br- ᴹ✶mrekjā > breig > N. braig ✧ Ety/MERÉK
mrekta- > brekta- mr- > br- ᴹ√MERÉK > N. breitha ✧ EtyAC/MERÉK
mrokō > brokō mr- > br- ᴹ✶morókō > N. brôg ✧ Ety/MORÓK

G. initial [n], [m] became [d], [b] before [l], [r]; [{mn}{lr}-] > [{bd}{lr}-]

HPG/§2.1

Order (03300)

Before 05300 [tl], [dl], [ðl] became [kl], [gl] ᴱ√nḷđ > G. glith GL/40

Phonetic Rule Elements

[nl-] > [dl-]
[nr-] > [ndr-]
[ml-] > [mbl-]
[mr-] > [mbr-]

Phonetic Rule Examples

mloss > mbloss ml- > mbl- ᴱ√mol- > G. Bloss ✧ GL/23
mritt- > mbritt- mr- > mbr- ᴱ√M(B)ṚTṚ > G. brith- ✧ QL/63
mritwen > mbritwen mr- > mbr- ᴱ√mṛt > G. Bridwen ✧ GL/24
nlið > dlið nl- > dl- ᴱ√nḷđ > G. glith ✧ GL/40
nrio > ndrio nr- > ndr- ᴱ✶n’reu̯ > G. †drio ✧ GL/30
nrip- > ndrip- nr- > ndr- ᴱ√nṛq- > G. drib- ✧ GL/30
nriθ > ndriθ nr- > ndr- ᴱ√nṛþ- > G. drith ✧ GL/30
nriθ- > ndriθ- nr- > ndr- ᴱ√nṛþ- > G. drith- ✧ GL/31
nrō > ndrō nr- > ndr- ᴱ√NORO > G. drô ✧ LT1A/Nornorë
nrok > ndrok nr- > ndr- ᴱ✶norokā́ > G. drog ✧ GL/31
nrond > ndrond nr- > ndr- ᴱ√NORO > G. drond ✧ LT1A/Nornorë