LOL I googled for ideas and it turns out that while in Sindarin, “Andreth” translates as “patience, long-suffering”, in Quenya, its closest equivalent, “Coloitië”, translates as “endurance, staunchness, fortitude” – the same thing, but a very different connotation. I like to think Aegnor liked to translate her name in an affectionate way, but Finrod never did, but was also the only one who took note of the connotation difference.
I think “Saelind” was originally just a snarky nickname Beril called her when she bossed him around, but in the grand tradition of Beverly Cleary’s Beezus (and uh, myself lol), the younger sibling-bestowed nickname took off among some of the adult crowd. Elves do canonically act like grown-up children right.
ephal ephalak idon hi-akallabeth 