In Sindarin, ⟨q⟩ or ⟨qu⟩ do not occur, so if we encounter it, the word
must actually be Quenya. Let’s be user-friendly and switch to Quenya in
that case (though I’m not sure how common it would be to encounter a
single Quenya word in a Sindarin text – I suspect it would be more
likely that the user chose the wrong language and really the entire text
is in Quenya).

According to Appendix E of The Lord of the Rings, ⟨k⟩ is used with the
same value as ⟨c⟩ in names from non-Elvish languages (both representing
/k/). However, in the Silmarillion, ⟨k⟩ is also used in some Elvish
names, such as Tulkas and Kementári, as well as in some words in the
Appendix (Elements in Quenya and Sindarin Names), e.g. kir- as an
element or root in Calacirya, Cirth, and other words. And in earlier
versions of the language (when Quenya was called Qenya and Sindarin
Gnomish), ⟨k⟩ also often occurs. Therefore, let’s support it as an
alternative spelling of ⟨c⟩.

Currently, eSpeak NG doesn’t seem to do the two-step replacement of
⟨kh⟩→⟨ch⟩→⟨x⟩, which means that ⟨kh⟩ is ultimately pronounced as /kh/
(or /kʰ/?) rather than [χ]; according to Appendix E, this is correct in
Dwarvish, while in Orkish and Adûnaic ⟨kh⟩ should be equivalent to ⟨ch⟩.
Since we’re not really aiming for pronouncing any of these languages,
either way is fine.

Consonants written twice always represent long consonants, not actual
repetation. eSpeak NG’s default behavior when speaking a doubled
consonant phoneme seems to work well enough for non-plosive consonants,
but for plosives, we need to tell it that the two input characters
correspond to one long phoneme, not a repeated regular one.

All three doubled voiceless plosives – ⟨tt⟩, ⟨pp⟩, ⟨cc⟩ – are regularly
found in Quenya, according to the Ambar Eldaron Quenya Dictionary [1].
Their voiced counterparts – ⟨dd⟩, ⟨bb⟩, ⟨gg⟩ – apparently don’t occur,
nor are any doubled plosives to be found in the Omikhleia Sindarin
Dictionary [2], voiced or not. But let’s define all six pairs in both
languages anyways, since it doesn’t cost us much to do so, and it seems
fairly clear that this is how these double consonants should be
pronounced, if they ever occurred.

[1]: https://ambar-eldaron.com/telechargements/quenya-engl-A4.pdf
[2]: https://www.jrrvf.com/hisweloke/sindar/index.html

⟨o⟩ almost certainly represents [ɔ] – Appendix E of The Lord of the
Rings describes it as the sound in English “for”. This means we should
use a phoneme [[O]], not [[o]]; we should also create our own phoneme
for this, since the one we inherit from Latin sounds much more like [o]
to me.

In Quenya, long ⟨ó⟩ (and, presumably, ⟨ô⟩) is, according to Appendix E,
“tenser and ‘closer’”, which presumably means [o]. (Online sources seem
to agree.) The Latin [[o:]] phoneme works well enough for this.

In Sindarin, ⟨ó⟩ has “the same quality” as ⟨o⟩ according to Appendix E,
so emit it as [[O:]] for [ɔː]. This sounds sensible enough te me.

I’m undecided whether “Lothlórien” should be in sjn_list, to pronounce
it with [oː] instead of [ɔː]. It’s composed of Sindarin “loth” and
Quenya “Lórien”, so that could potentially justify a pronunciation with
a Quenya ⟨ó⟩. But then again, maybe it should be a standard Sindarin
⟨ó⟩. For now, I’ve opted to not add it; in the film The Fellowship of
the Ring, Aragorn (Viggo Mortensen) says “Lothlórien” after the
Fellowship leave Moria, and to me his ⟨ó⟩ sounds more like [ɔː] than
[oː], so if this is wrong, at least it’s no more wrong than the famous
movie adaptation :)

⟨e⟩ almost certainly always represents [ɛ], not [e]. Appendix E of The
Lord of the Rings describes it as the sound in English “were”, and I’m
not aware of any English dialect that pronounces “were” with an [e].

In Quenya, long ⟨é⟩ (and, presumably, ⟨ê⟩) is, according to Appendix E,
“tenser and ‘closer’”, which I assume means [e]. Several online sources
agree with this as well.

In Sindarin, Appendix E is quite clear that ⟨é⟩ has “the same quality”
as ⟨e⟩, only differring from it in length: I assume this must mean that
⟨é⟩ is [ɛː] in Sindarin. The online information on this is confusing and
sometimes contradictory even within the same page; several sources claim
that Sindarin has an [eː], but I have not seen this claim substantiated
with a source from Tolkien, and I suspect it’s simply a confusion with
Quenya. It scarcely matters, anyway: Sindarin words with ⟨é⟩ or ⟨ê⟩ seem
to be pretty rare. (I’m aware of a single word with an ⟨é⟩ – the name
Eluréd, son of Dior – and the Omikhleia Sindarin dictionary [1] features
some words with ⟨ê⟩, giving their pronunciation with [ɛː].)

The [[EI]] phoneme for Sindarin ⟨ei⟩ is copied from the base2 phonemes.

[1]: https://www.jrrvf.com/hisweloke/sindar/index.html

Previously, we used vdiph/ui_4 for [[ui]]; I think the main reason for
that was that I didn’t like how the most common ⟨ui⟩, vdiph/ui, seemed
to almost vanish in “Cuiviénen”. However, vdiph/ui_4 has the curious
property that in some positions, e.g. ⟨uia⟩ in “tuia” or ⟨uil⟩
“tuilindo”, it sounds (to me) more like /ul/ than /ui/. (This also
affects Finnish, which seems to be the only other language that uses
vdiph/ui_4 [a few other languages also use it for [[ui]] but don’t seem
to emit that phoneme in their rules files] – listen to eSpeak NG
pronounce Finnish ”luiun”, for instance.) I eventually found out that
this can be worked around by substantially lengthening the phoneme
(length 500 seems to work in all positions), but this extreme length
(the absolute maximum is just 511) becomes rather noticeable whenever
the ui is used, including in positions where it had sounded just fine
before. Meanwhile, the more standard vdiph/ui can be made to sound
reasonably well in “Cuiviénen” with a much smaller increment to its
length: 290 (as also in ph_lithuanian) instead of 240 (as in ph_base2)
is enough. In this version, [[uI]] sounds acceptable enough for Elvish
⟨ui⟩ in all positions, as far as I can tell.

This is “a voiceless w, as in English white (in northern pronunciation)”
according to Appendix E of The Lord of the Rings, and so we copy the
[[w#]] phoneme from the English phonemes. I can’t actually hear much of
a difference from the previous [[hw]] (I know what the difference
between [[w]] and [[w#]] should be, but [[hw]] already sounds like
[[w#]] to me), but at least this improves the --ipa output, changing it
from [hw] to [ʍ].

Both represent a “voiceless R”, which I believe means a voiceless
alveolar trill, [r̥]. Ideally this would be one phoneme, but I’m not sure
eSpeak NG currently has a phoneme for this. The Wikipedia article [1][2]
lists occurrences in comparatively few languages, and I chose Welsh for
guidance: eSpeak NG currently turns Welsh “Rhagfyr” into [[hr'agvYr]],
and [[h]] and [[r]] are apparently just two separate phonemes, so for
now we do the same for Quenya and Sindarin, and emit hR.

[1]: https://en.wikipedia.org/wiki/Voiceless_alveolar_trill
[2]: https://en.wikipedia.org/wiki/Special:PermanentLink/1024721264

Both represent a “voiceless L”; Appendix E of The Lord of the Rings
notes that the Quenya ⟨hl⟩ was pronounced like /l/ by the Third Age, but
for now we reproduce the original pronunciation. (Maybe we can later use
conditional rules for different pronunciations, but I think for now I
won’t go down that road.)

The B-side of the album Poems and Songs of Middle Earth begins with a
reading of the Sindarin poem A Elbereth Gilthoniel by J.R.R. Tolkien
himself, and in this recording, as best I can tell, he always pronounces
short i (i.e. ⟨i⟩, not ⟨í⟩ or ⟨î⟩) as /ɪ/ rather than /i/, regardless of
stress; for instance, the word “silivren” has the same i-sound twice (it
is not “silívren”). I believe this means that we should use the phoneme
[[I]], not [[i]], for ⟨i⟩ (in both Quenya and Sindarin).

Appendix E of The Lord of the Rings describes it as “the sound heard in
bach (in German or Welsh)”; I think that means [χ], not [x] (voiceless
uvular rather than velar fricative), and out of the base1 phonemes,
[[X]] is closer to that than [[x]]. (The German phonemes redefine [[x]]
to be closer to [[X]], if I’m not mistaken, but I don’t think we need
that. Note also that we actually need [[x]] for Quenya ⟨ht⟩.)

Stress is determined based on the syllables, not the vowels, so the
diphthongs need to count as a single syllable. If there is a diphthong
at the end of a word, the penultimate syllable can still be unstressed
if it is light. (The name of Arvedui, last king of Arthedain, is one
example of this that I could think of, but I’m sure it’s not the only
one.)

Using a + is simpler than an additional rule, and scales better if more
rules are introduced later. (A single + seems to be sufficient.)

For ⟨ae⟩, we used to use the Latin [[aI]] phoneme, which sounds like
/ae/. Call that phoneme [[aE]] for us and introduce a separate [[aI]]
one, which sounds more like /ai/ (since Sindarin has both, and they’re
supposed to sound different, though Appendix E of The Lord of the Rings
notes that there is nothing closely corresponding to ⟨ae⟩ in English and
that it may be pronounced like ⟨ai⟩). Furthermore, for ⟨oe⟩, just remove
the TODO – the Latin phoneme is called [[OI]] but sounds more like /oe/
than /oi/, so it’s actually just fine for our purposes. Finally, the
⟨ui⟩ diphthong is copied from Finnish, just like in Quenya.

According to Appendix E of The Lord of the Rings, ⟨ph⟩ stands for /f/
when final (because ⟨f⟩ is pronounced as /v/ in that position), and
otherwise is used instead of ⟨f⟩ either because it’s derived from ⟨p⟩
(in which case it’s presumably pronounced just like ⟨f⟩), or to
represent an especially long /f/. We can’t really tell which case we
have, but from the Omikhleia Sindarin dictionary [1], it appears that
all the long ⟨ph⟩’s are between two vowels, and all the short ones have
at least one adjacent consonant, so let’s use that as a rule and hope it
works out. (The Ambar Eldaron Quenya dictionary [2] is less easily
searchable, so I’m just hoping that this rule works reasonably well for
both languages.)

[1]: https://www.jrrvf.com/hisweloke/sindar/index.html
[2]: https://ambar-eldaron.com/telechargements/quenya-engl-A4.pdf

Not all of the diphthongs in Quenya and Sindarin are defined in the
Latin phonemes, and for now we’re sticking to those, so some diphthongs
just get TODOs for now. Also, we’re temporarily using the same phoneme
for ⟨ae⟩/⟨ai⟩ and ⟨oe⟩/⟨oi⟩, which should really be different (though
Appendix E of The Lord of the Rings notes that ⟨ae⟩ and ⟨oe⟩ don’t have
close English equivalents, and that they “may be pronounced as ai, oi”).

A circumflex “specially prolonged” vowels; according to Appendix E of
The Lord of the Rings, only in Sindarin, but the Ambar Eldaron Quenya
Dictionary [1] also has some very few circumflex words (sû, lîs), so
let’s support the circumflex in Quenya as well. Marking extra-long
vowels with two colons seems to work well and is also done in several
other languages.

[1]: https://ambar-eldaron.com/telechargements/quenya-engl-A4.pdf

Long vowels, marked with an acute accent or a circumflex, are longer
than short vowels (duh) and always make a heavy syllable (i.e. we don’t
include the rules to move stress to the previous syllable). In Quenya,
⟨é⟩ and ⟨ó⟩ are “tenser and ‘closer’” than the short vowels, according
to Appendix E of The Lord of the Rings, while in Sindarin they’re
supposed to be the same; the phonemes we inherit from Latin seem to
reproduce this reasonably well for Quenya, and for now we use them for
Sindarin too, which works nicely for the most common Sindarin word with
a long o, “Lothlórien” (because Lórien is actually a Quenya name, and
therefore I assume *that* ⟨ó⟩ should actually be /o/ and not /ɔ/). I
might adjust the phonemes later (at which point Lothlórien will
presumably have to go in sjn_list).

In Elvish languages, ⟨ch⟩, ⟨dh⟩, and ⟨th⟩ count as single consonants for
the purposes of stress, since they represent single letters in the
original scripts. The easiest way to implement this is to replace them
with single letters at the beginning – ⟨ð⟩ for ⟨dh⟩ and ⟨þ⟩ for ⟨th⟩ are
natural, and ⟨x⟩ for ⟨ch⟩ also makes some sense, though it means we need
to replace real ⟨x⟩ first (it’s not mentioned in Appendix E of The Lord
of the Rings, but does occur in some Quenya words, notably Helcaraxë).
Real ⟨x⟩ is pronounced like /ks/, but of course we need to spell that as
⟨cs⟩, since ⟨k⟩ does not occur in Elvish languages.

The Elvish languages have the same general stress rule as Latin [1]:
stress falls on the penultimate syllable if that is heavy (contains a
long vowel, a diphthong, or a vowel followed by two or more consonants),
otherwise on the antepenultimate syllable. For Latin, espeak-ng
implements this by declaring “penultimate syllable” as the general
stress rule in espeak-ng-data/, and then adding rules in dictsource/
that match light syllables and move the primary stress to the previous
syllable, i.e. the antepenultimate one. We use the same basic principle
for the Elvish languages here (but using the terms “heavy” and “light”
rather than “weak” and “strong” like in the Latin files).

Note that this doesn’t fully implement the stress rules yet: we have no
concept of diphthongs, long vowels aren’t really properly handled yet,
and we also still count ⟨ch⟩, ⟨dh⟩, ⟨th⟩ as two consonants rather than
one as it should be. This will be improved separately (I prefer doing
this in small incremental steps).

[1]: https://menegroth.github.io/stress-in-sindarin.html

Sindarin ⟨i⟩ is only pronounced like ⟨j⟩ before another vowel and *at
the beginning of a word*. “Galadriel” does not have a /j/ sound.

Also, inherit the Elvish phonemes from Latin, because Esperanto doesn’t
have /y/. (Quenya doesn’t need that – ⟨y⟩ is a consonant there – so
maybe I’ll separate their phonemes at some point. For now, Latin works
well enough for both as far as I can tell.)

This prepares the languages of Quenya and Sindarin, setting up their
infrastructure without declaring a lot of rules yet – just enough for
“Eä” (a Quenya word, but I can’t think of a similarly simple one for
Sindarin). Phonemes are inherited from Esperanto for now.