No I think it is a silent letter
the schwa is a the neutral syllable and is the undotted i in Turkish
if you think about the Essex bottle - /bo''ul/
the apostrophe is a glottal stop - sorry glo''al stop
and the /u/ is the schwa - neutral sound of which there are a profusion in English. IPA sign is an upside down 'e'
Anglo Saxon was full of final unstressed vowels which became schwas and then dropped off completely - -
http://en.wikipedia.org/wiki/Final-obstruent_devoicing which I was looking at earlier on in the day