Comment Sorry, but no (Score 1) 225
Neither Washoe nor any other non-human primate has learnt sign language in any meaningful way -- not anything that stands up to a bit of critical review. They were certainly smart -- smart enough to learn "If I mimic enough of these signs eventually someone will give me a banana". They were also followed around by credulous 'researchers' who were eager to interpret any hand wave as highly significant, and who in fact so credulous that they didn't notice that most of the time the primates were simply mimicking back to them a gesture that they had just made.
If you want an assessment of how close they were to using sign language, ask someone for whom sign language is a first language to take a look. Without exception, native signers are unimpressed.
As far as parrots go, they're not learning to talk, or learning words -- they're learning to imitate sounds. There's no difference, as far as the parrot is concerned, between "polly want a cracker" and a squawk.
There are lyrebirds near where I live which have learnt to make laser sounds from when there was a laser skirmish being run in the bush. Hearing them make laser sounds at each other is amusing, but no-one ever suggests that they have learnt to play laser skirmish from humans and therefore lyrebirds must have the same game-playing abilities as humans.