Why are Mandos and Lórien described by a noun in plural form? They are two and that should require the dual ending, shouldn't it?
By the way: What would the dual form look like? Or in general: How do we decline a noun, which results in a consonant?
In some cases it's clear (like singular genitive and most plural cases), but what about those forms, which require suffixes, which start with a consonant too (collective, dual and most singular cases)?
I have read in one source that the connecting vowel between the word's end and the (dual) suffix (-t/-lto/-to/...) always has to be -e-. In this case, the dual form would be "feanturet". Is that true?
In another source I have read that we have to duplicate the last vowel of the word, so that it would be "feanturut". What is right?
PS. I forgot the other dual ending: -u. Probably it should be feanturu, especially if we consider that Mandos and Lórien are brothers. Therefore I specify my question about nouns, which result in a consonant: What vowels are required in front of the -t dual variant/all the other case-suffixes which start with a consonant?
A name used collectively to describe Mandos and Lórien, the “Masters of Spirits” in Death and Dreams, respectively (S/28). This name is a plural compound of fëa “spirit” and the suffix -tur “master” (SA/fëa, tur).
Conceptual Development: This name dates back to the earliest Lost Tales, in the form ᴱQ/ᴹQ. Fanturi (LT1/79, LR/205), but in earlier writings it was often used in its singular form Fantur, especially in compound sobriquets of Mandos and Lorien: ᴱQ. Vefántur, ᴹQ. Nurufantur “Fantur of Death” for Mandos and ᴱQ/ᴹQ. Olofantur “Fantur of Dreams” for Lórien. This earlier form was glossed “Lord of Cloud” in The Etymologies from the 1930s, combination of fána “cloud” and -tur “lord” (Ety/SPAN, TUR).
In Silmarillion revisions from the 1950s-60s, the names Mandos and Lórien became the sobriquets, while their true names were Námo and Irmo (S/28, WJ/402-3). Fanturi became Fëanturi and was only used collectively (MR/145).