Many years ago I heard a recorded lecture entitled "Good Speech." I have forgotten the advice it contained, but if that speaker were here today I think he would have to start all over again. I think he would suggest a new approach to vowel sounds. A, E, I, O, U are our written vowels, but our sounding vowels are thirteen in number, and are used in this sentence.
"Badding Practise in Cennerfield?,"
Word Ways: Vol. 9
, Article 7.
Available at: http://digitalcommons.butler.edu/wordways/vol9/iss4/7