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).