Speakers enable you to post messages on campus. In order to obtain speakers you can exchange extra credits for speakers in the store (scroll right down to the bottom of the store). To get extra credits, you can buy them using real money from the nurse, or by doing any job, jobs have a 2% chance of dropping extra credits.
You can also get free speakers from pimd once a day once you've opened 6 dorms.
Tutors are other players that you have hired.
Volley'ing is when two or more players hire back and fourth a tutor in quick concession.