Teaching Parrots
It is possible to 'teach' parrots to repeat speech actions. The exact mechanism is unknown, but circumstantial evidence has proven that repeating a sentence five times when on the same square as a parrot will result in it 'learning' the phrase and, ahem, parroting it randomly in the future.
What is unknown is:
1/ Whether it is possible to teach parrots phrases by repeating it less than five times, or if there is a percentage chance of a parrot learning a phrase.
2/ Whether parrots learn phrases individually, or all the parrots on the island have a collective library of learned phrases. There is anecdotal evidence for both. On the one hand, it has been noted that a parrot has repeated the taught phrase immediately after it was taught it, which would suggest this was the only phrase it knew. On the other hand, a parrot has been recorded repeating a phrase long after it would have been expected to have been killed - although there is a distinct possibilty that multiple parrots were taught the same phrase. Still, this occurence does suggest that parrots have a shared vocabulary.
3/ Whether, if parrots are taught individually, each new phrase overwrites any previous, or is added to its repetoire.
4/ Whether, if parrots have a collective vocabulary, the number of parrots taught a particular phrase affects the liklihood of that phrase being repeated by other parrots.
Various forum threads covering parrotological vocabulary:
http://forum.shartak.com/index.php/topic,1583.0.html