Someone who is very easy to talk to. Can be talked to about any subject that the talker wants to talk about. Can often be found dispensing useful advice, empathizing or telling bad jokes to see who laughs.
-I say, that chap Jethro is rather "talk-toable"
-yes, he is quite a laugh is he not
-would you like a bit of crumpet, Edmund?
-why yes i would, thank you ever so kindly
-hey why was the chicken so happy?
-I dunno, why?
-because everything was eggcellent