User:Jnestorius/Rules for indefinite article An

Use "an" where the word starts with a vowel sound, not necessarily a vowel spelling.
 * A apple aorta aura awful art
 * E end eat either
 * Eu euphoria Europe from Greek
 * Euler from German
 * Ew ewe ewer
 * Ewald's sphere from German
 * I ill idiot: even for i (as opposed to j) Iago? Iosco County, Michigan? iatrogenic iodine ion Iowa Iolanthe Iona iota
 * Ionesco, Ion Iliescu from Romanian
 * Ioannina from Greek
 * Ieuan Wyn Jones from Welsh
 * O on out oat oil odd order
 * one once irregular
 * Oaxaca from Spanish
 * Ou always? French ouija Ouachita Ouimet Ouagadougou Ouida Ouest-France
 * Oi- if French Oise
 * U up uh um under utter ugly
 * U unit ukelele Uganda Uruguay? Ulysses
 * ux- uxorious
 * Up- Un- upend unused
 * Ubangi Urumqi Upanishad Umayyad Uluru exotic loanwords
 * Uighur
 * Uitlander Afrikaans
 * Uelzen German
 * Ueno Japanese, 2 syllables.
 * Uillean pipes, Irish
 * Ustinov? Ukraine?
 * Ueberroth?
 * Uinta Mountains? apparently uintasurus is yoo-inta
 * Uachtarán from Irish
 * uakari Uaxactun, Ueuecoyotl from Spanish
 * Uaboe,Nauru
 * Uasin Gishu District Kenya?
 * Y ylang-ylang yttrium Ypsilanti words exotic but rule is standard
 * Y yes yellow
 * Yemanja?
 * Hour, Hono(u)r, Heir, Honest, (Herbal) only common French words
 * Historic, Hotel unstressed first syllable, French-origin

Marginal

 * Xavier occasionally as in the X-Men's Professor X
 * Ndebele, Nkrumah, Mbabane, Ngugi syllabic nasal consonants

Letters

 * initialisms NAACP
 * not acronyms NASA
 * F-plan H-bomb L-plate M N R S X-ray
 * U-boat Y-fronts