Let’s start with a landing page for all English vowels. A catch-all where you then navigate to the individual vowel sounds you might want to learn more about later.
This page will talk more generally about vowels as a whole category of sounds rather than the specifics. Again, vowel sounds may not be consistently represented by the same vowel letter. As a result, i will be careful with my wording to indicate vowel SOUND versus vowel LETTER.
This is already an issue I’ve raised with different consonants in English.
Well, English vowels can be worse with their inconsistencies.
In English, the written representation of vowels falls into A, E, I, O, U and sometimes Y.
6 letters. But, each vowel doesn’t always make the same sound.
For example:
So, it is still 100% important to LISTEN when you are practicing your English pronunciation for the sound more than you trust the spelling.
When talking about vowels, there are 3 features that people use to describe the pronunciation.
The main descriptors that vary between vowels are as follows:
tongue height (vertical dimension),
tongue backness (horizontal dimension)
and roundedness (lip articulation)
There are additional features as well such as nasality but these are the main 3 to focus on.
This conception of vowel articulation has been known to be inaccurate since 1928. So it 100% is not the greatest method or actually correct in all situations but it is a good starting point because of how abstract the concept is. Per Wikipedia, “Peter Ladefoged has said that "early phoneticians... thought they were describing the highest point of the tongue, but they were not. They were actually describing formant frequencies." Now, formants are based on measurable data that you can analyze on a graph, but become again, becomes an extremely arbitrary concept to your average person (See here for more information if you’re interested.)
So as a next best thing with no other better model, we're using the vowel quadrilateral. Just remember, it is not a direct mapping of tongue position and is an abstraction.