I asked my English teacher about pronunciation of words like table, available, apple or people. He told me they end with a short A. But when I listen to native English speakers, I hear "pee-pole", which seems like a short O to me.
The phonemic pronunciation of people is /ˈpi pəl/. So the first syllable is stressed, and the second is weaker (PEO-ple).
The upside-down "e" in the second syllable is called a schwa, and it represents a "neutral" vowel. The Random House definition of "schwa" gives as examples:
the sound of a in alone and sofa, e in system, i in easily, o in gallop, u in circus.
The Cambridge Dictionaries online write this as /ˈpiː.pl̩/, indicating a much shorter vowel in the second syllable.