Longhorn: Andras or Anras?

I've been dabbling with construction neo-sindarin neologisms for a project in another one of my areas of interest and I came across this case that I thought was ambiguous.

And (long) appears as 'and' in the compounds: andaith, andram, and also andreth, among others.

It appears as 'an' in anfang, anfalas, annas, anras(t), and (depending on which word dropped the d) anduin.

Would andras or anras be more proper? Andras seemingly already refers to 'long cape', since the t is dropped from 'rast' in that word, but I suppose Sindarin would be far from the first language to have homonyms.

While I'm at it, is enrais/endrais a correct pluralization for longhorns?

Welcome! anda·rasse > anda·rass > andrass > andras is what I would come up with. We have numerous compounds attested with the cluster -ndr-.

Plural would be endrais

And I suppose you could use N. taen², adj. “long (and thin)” for taedhras (pl.) taedhrais. but I am wondering if this might be one of the special cases where ae reduces to e. So possibly tedhras and tedhrais.

Thank so much for your help with it, I'm glad I wasn't too far off base.

If you don't mind, could you talk a little about the process you used to come up with your answer? My approach was mostly educated guessing based on the examples that are available. Are you reconstructing each noun in the compound from Quenya?

Sure, so I brought it back to Primitive Elvish and brought it through Phonetic Developments, and Quenya would be andarasse. I believe Quenya is not my strongest suite. Now you don't always have to go back to Primitive Elvish, I was just kind of showing the process.

So

• anda·rasse 024 short final vowels vanished
• anda·rass 036 short vowels vanished before morpheme boundaries
• andrass 063 final [ll], [nn], [ss] shortened in polysyllables (S = Syllable)
• andras

I hope that helps, there about 150 rules in general.

If you'd like to become familiar with the phonetic developments yourself, you can look at eldamo.org. If you click on Primitive Elvish, Ancient Quenya, and Quenya, you can find lists of phonetic rules.