Many elven words come in and are given different significance based on the key vowel located within the word. Sometimes, this means a completely new meaning to the word. Other times, it can be an almost identical meaning, with a slightly different significance.
The vowel 'u' is given the least significance, and a noun containing the hard u sound is often considered foul, or vulgar. In fact, the word vulgar itself, in common, finds its etymology in elven.
The other vowels, in order of significance, are o, a, i and finally e. In the usage of significance, y and modified vowels are not used.