at hearing one has got a fortune . . . at last . . . whom I had never heard . . . at a table . . . (Jane Eyre)
If Jim Dale (who reads the Harry Potter series) had read Jane Eyre, I think he would have pronounced all the a sounds as schwa /ə/; yet a recording on Librivox.org has the /ӕ/ sounds. The former is more natural while the latter more punctual. After hearing the audio book, I wonder which pronunciation is more common. Would you let me know?
Purely functional words are never stressed, and thus are subject to vowel-reduction into schwas.