5 vowel words
A STHM A begins and ends with a vowel and has no other vowels in between. Some less common long words with this property are I STHM I (alternate plural of isthmus), A PHTH A, and E LTCH I.
Note that we are talking about the five true vowels in the English alphabet: A, E, I, O, and U. Sometimes the consonant Y may be pronounced as a vowel, as may other letters in rare words, such as W in some words of Welsh origin.
They are ordered by length. The shortest words are just seven letters (containing just two additional consonants), and the longest word, HYDROMETALLURGISTS, is eighteen letters long.
ARSENIOUS  FACETIOUS  ABSTEMIOUS  ABSTENTIOUS  FACETIOUSLY  ABSTEMIOUSLY
- Short pronunciation: “My hat sat on the mat.” (hăt, săt, măt)
- Long Pronunciation: “He ate the date on my plate.” (āte, dāte, plāte)
For example, Standard American English has fewer vowel distinctions than Standard Southern British English, so while a Londoner from Mayfair would likely pronounce the words “merry,” “marry,” and “Mary” in three clearly different ways, these three words sound pretty much the same to the majority of Americans.
Basically, a vowel is a sound that is made with the mouth and throat not closing at any point. In contrast, a consonant is a sound that is made with the air stopping once or more during the vocalization. That means that at some point, the sound is stopped by your teeth, tongue, lips, or constriction of the vocal cords.
Another forgotten letter that has the same qualities as “y” is “w.” While “w” is almost always a consonant, it is considered a vowel at the end of words like “wow” or “how.” You can see for yourself when saying these words that your mouth doesn’t fully close while pronouncing the letter.