Ancient Quenya Phonetics P21: syllabic nasals developed a preceding vowel of similar quality

AQ. syllabic nasals developed a preceding vowel of similar quality; [ṃb-|ṇd-|ŋ̣g-|ŋ̣gw-|ŋ̣gj-] > [umb-|and-|iŋg-|uŋgw-|iŋgj-]

Primitive Elvish words allowed for initial nasal-stop clusters (PE18/43-44, 93), and in some cases those initial groups became syllabic. The exact conditions under which this syllabification occurred isn’t entirely clear, though sometime in the last 1950s or early 1960s Tolkien said “but in some cases, usually words of strong or emotional meaning or important names, the nasal became syllabic” (PE17/124). In the 1930s he wrote:

Ancient Quenya Phonetics P20: voiced stops became nasals before nasals

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

In Ancient Quenya, voiced stops became nasals before nasals, a sound change Tolkien described in both the Outline of Phonetic Development [OP1] from the 1930s and the Outline of Phonology [OP2] from the 1950s:

Ancient Quenya Phonetics P17: initial [s] plus voiceless stops became voiceless spirants

AQ. initial [s] plus voiceless stops became voiceless spirants; [sp-|st-|sk-] > [ɸ-|θ-|x-]

An initial s followed by a voiced stop developed into a voiceless spirant of the same quality: sp, st, sk > f (or ), þ, χ (IPA [f] or [ɸ], [θ], [x]). A similar change occurred in Sindarin. Tolkien discussed this sound change in both the Outline of Phonetic Development [OP1] from the 1930s and the Outline of Phonology [OP2] from the 1950s:

Ancient Quenya Phonetics P16: aspirates became voiceless spirants

AQ. aspirates became voiceless spirants; [{ptk}ʰ] > [{ɸθx}]

Any aspirates that survived other changes became voiceless spirants in Ancient Quenya. Examples of this phonetic development are extremely numerous. Tolkien gave essentially identical descriptions of this sound change in both the Outline of Phonetic Development [OP1] from the 1930s and the Outline of Phonology [OP2] from the 1950s (PE19/71):