It’s a well known fact that, in English, the way a word is spelled can have little or no relationship to the way it’s pronounced. As a native speaker of Romanian, which is a phonetic language, I find the pronunciation of single vowels particularly confusing.
To illustrate, here’s a completely non-scientific correspondence between what an English speaker thinks he’s saying and what my brain translates it to:
|Letter||What I hear|
Because of this, my chances of ever winning a spelling bee contest are severely handicapped.
Update: Here is comprehensive treatment of the consonants: How selected consonants sound around Europe, in 9 maps