What tales had you in mind? Apart from Noah sending out a raven from the ark to test whether the flood had subsided ( Genesis ch 8 v 7 ) none come to mind. There are loads of stories of ravens being involved as messengers who could talk though. Nobody seems to have taught one to talk save for the gods and mythical magicians. In Norse myth Odin kept two ravens to fly around the world each day to report back all the news ( once they'd got their breath back). He called them , in witty and original Norse manner, Thought and Memory ( because 'they kept coming back to him' ?) All over the world (except New Zealand where there are no native crows) there seem to be similar stories of ravens being messengers of gods or from the Underworld ; they are associated with death, but then they eat exposed corpses and all carrion.They are known to be intelligent birds. The Irish still say' he/she has raven's knowledge' for anyone who seems deep and all-knowing. But as carrier ravens in real life? No, apparently