Coin names and slang: adding character to games with ease

Most custom settings seem to consist solely of a generic map and a custom pantheon, which doesn't do much in my opinion apart from boring the players while the GM rambles on about how Qwertix defeated Zyxx and so on, which does nothing for the players or, worse, proscribes a clerical domain or two. So how does one spice up a custom game?
It is often said that the theme is key, however this may result in a gargantuan job, so minor details are easier to pull off.

Oathbow

The Oathbow in D&D has the flavour that it wishers "Swift defeat to my enemies" in Elvish, yet does not say what it is. In Sindarin it is "dant lagor anin gyth nîn".

D&D character sheet in Sindarin (Elvish)

In Tolkien's universe, Elves speak a variety of elvish languages. As JRR Tolkien was a professor of Old English at Oxford, he knew his stuff when it comes to linguistics, so like Klingon and Valyrian, Elvish is not a crackpot's attempt at a language (unlike too many made-up sentences in movies with jarring mistakes). Tolkein Elvish is a family of languages, which include Quenya, nicknamed Latin-Elvish, and Sindarin, common Elvish. The script is called Tengwar. The character sheet is written in Sindarin using the Tengwar script.