LONG VOWELS

 This unit is about long vowels. English language has five long vowels sounds such as: iː,aː,uː,ɔː,ɜ ː. The main characteristic is that long vowels sounds are followed by the voiced consonants sounds. For example /b,v,g,z/ sounds. Also, in this unit studies the position that have each one such as:” iː it is closer and more front, aːthis is an open vowel, and the lips position is neutral, uːit is much less back and less close,ɔːthe tongue height for this vowel, closer to the latter and ,ɜ ːit is a mid central vowel which is used in most English accents”.

Reference: 

Peter Roach, English Phonetics and Phonology,Cambrige Universiy, New York ,2009

http://www.youtube.com/watch?v=pY6EZjcDZdA