Confirmation that someone is listening to another person's speech

When someone is telling you a very long and detailed story he usually wants to hear some "confirmations" (or response) that you are listening to his story. In Russian we often use something like "tak" (which has a meaning of "ok" and "well, proceed further"), "a-ha" or "uh-huh".

What word serves the same purpose in English and American English?

The use of such verbal and non-verbal markers has a name (backchannelling), and has been the subject of studies ( see http://en.wikipedia.org/wiki/Backchannel_(linguistics) ).

They form a subset of discourse (better, pragmatic) markers (http://en.wikipedia.org/wiki/Discourse_marker ), obviously of the 'oiling the wheels of discourse' variety - though they grade into replies containing semantic feedback ('I see!' 'Never!').

There are many words and noises that English speakers make to indicate that they're still listening. Yes, ya, uh-huh, m-hm, right, OK. Also nods and eye contact.

Edit.

This subject is discussed a little more here. Look especially at:

• Use encouraging words to show you are listening.
  • "Mmm, hmm"
  • "I see."
  • "Right."
  • "Uh, huh."
• Use nonverbal actions to show you are listening.
  • relaxed posture
  • head-nodding
  • facial expression
  • relaxed body expression
  • eye contact