In Ancient Quenya any χ [x] (derived from [kʰ]) combined with a semi-vowel y or w unvoiced the following sound. This sound change occurred both initially and medially. The net result was a voiceless y that Tolkien transcribed ɧ or hy (and seems to be pronounced as a more frictional [hj]) and a voiceless w that Tolkien transcribed as ƕ or hw (and seems to be pronounced as a more frictional [ʍ]). This lexicon uses [j̊], [w̥] in its phonetic notations for consistency with other voiceless sounds. These sounds merged with the phonetic developments of initial sy- and sw-, as hinted at in The Lord of the Rings Appendix E.

HY was usually derived from sy- and khy- (LotR/1115)

Tolkien described this sound change in both the Outline of Phonetic Development (OP1) from the 1940s and the Outline of Phonology (OP2) from the 1950s:

khy became χy with [χ] fronted. The ultimate result was a strong voiceless y [ɧ] here transcribed hy — similar to (but more strongly spirantal than) the sound of English “huge” ... khw became [χw]. This combination was rare except initially. There, parallel to the development of khy, it became spirantal voiceless w [ƕ]. It was more tense and spirantal than English (northern) initial “wh-” (OP1: PE19/34-5).

khy became first [χy] with voiceless y and marked fronting of the [χ]. The result already in PQ was initially and medially a strong voiceless y [ɧ], here transcribed hy, similar to, but more frictional than the initial sound in English “huge” ... khw became first [χw] with unvoiced w. Parallel to the development of khy this became in PQ a spirantal voiceless w [ƕ]. It was more tense with closer lip-aperture and more friction than the voiceless “wh” of English. This combination was in CE rare medially, but not uncommon initially. It is here transcribed hw (OP2: PE19/75).

These sound changes can also be seen in the Comparative Tables of phonetic developments from the 1930s (PE19/18). The sound change khy > hy must have occurred before velars were dentalized before [j], because there is no sign that khy > thy. Tolkien made this explicit in notes from 1930s:

Note khy did not become thy, but produced [χy] with fronted [χ] a strongly spirantal (long) voiceless [y], [ɧ] transcribed hy (OP1: PE19/40).

This also means these unvoicings probably began before the more general sound change whereby [x] became [h] (which did not occur until Parmaquesta), though they were probably driven by the same forces. Examples of khy > hy can be found in the 1930s through the 1960s, but explicit examples of khw > hw are difficult to find:

• ✶khyana > Q. hyana “other” (VT49/14).
• ᴹ√KHYEL(ES) > ᴹQ. hyelle “glass” (Ety/KHYEL(ES)).
• ᴹ√KHYAR > ᴹQ. hyarmen “south” (Ety/KHYAR), an example Tolkien mentioned again in LotR Appendix E.

In the 1930s, Tolkien also indicated these sounds were the result of initial sky-, skw- > χy-, χw- > ɧ-, ƕ- (OP1: PE19/36). Examples include:

• ᴹ✶skyapat- > ᴹQ. hyapat “shoe” (Ety/SKYAP).
• ᴹ√SKWAR > ᴹQ. hwarin “crooked” (Ety/SKWAR).

However, sometime in the 1950s, he decided these initial combinations were no longer possible in Primitive Elvish (PE19/78, note #51).

Conceptual Development: Tolkien’s earliest conception of Primitive Elvish from the 1910s and 1920s already had voiceless palatalized and labialized spirantal sounds, which Tolkien transcribed χ̑ (or þ͡y) and x͡w (PE12/15). The palatalized sound developed initially into hy- in examples from the Qenya Lexicon: hyá “here by us” and hyanda “blade” (QL/41). However, medially Tolkien seems to have denoted this sound as Ẏ in early primitive roots and it developed into an ordinary voiced y.

There are no clear examples for the development of x͡w- in the Qenya Lexicon, but charts in the Qenya Phonology indicate it became hu̯- [hw-] in the Kor-Eldarin period but later f (PE12/16). The more detail description of its initial development states that it generally became f initially except before u where it became h (PE12/17). There is some evidence of this initial development to f/h in the Qenya Lexicon: ᴱ√ǶUẎU > ᴱQ. hui or fui (QL/41). Medially it was denoted Ẇ and became ordinary voiced w.

Somewhat interestingly, the description of the phonetic development of χ̑ in Qenya Phonology states that it generally became hy initially but sometimes became s dialectically (PE12/18). The chart on its development in the Kor-Eldarin period shows that it passed through the sound sı̯- [sy-] (PE12/16), perhaps representing a labialized s or a voiceless co-articulated sy-sound (IPA [ɧ]). This is the only evidence I have found that Tolkien’s use of ɧ as an alternate representation of hy might match its common IPA usage.

Note that in the 1930s, Tolkien flirted with the idea that sy, sw also merged with khy, khw medially as well as initially to become (long) voiceless hy, hw (OP1: PE19/49, 50). However, there is no evidence of this in contemporaneous examples, where medial -sy- > -ry-: ᴹ√PIS > ᴹQ. pirya “juice” (Ety/PIS). These sound changes sy, sw > hy, hw reappear in the table for medial developments in OP2 (PE19/80) but not in the main body of the text where the normal medial development was sy, sw > zy, zw > ry, rw (PE19/102). This matches all the examples from the 1950s and 60s, so it seems likely the concept of medial unvoicing for sy, sw was ultimately abandoned.

@@@ initially and medially, vs. Late Q. where sy, sw > voiceless y, w only initially