Yeah, I've experienced that with Ss, but not all of them. Some Ss are very deep and are great listeners, I find. At the same time, I have gone on some pretty disasterous S dates. We just run out of things to talk about and are much better off if we just do stuff together. I do sometimes wonder if they are dumb when I ask a question and they can't come up with the words to answer it, but then you watch them talking to other Ss and they are some of the most intelligent people I've ever met. To be fair, I'm pretty sure they feel the same way about me when I cannot talk about anything concrete (although, I've been working on it)!
Wild!
Example. I asked this ESTJ to tell me about his friend...
ME: "Tell me what your best friend is like!"
HIM: "You always ask me this! I can't describe people... I can tell you where they are from and what they do, but I don't think that's what you want to know..."
I mean, I'm like... how can you not possibly know how to describe someone? But, it seems the vocabularly simply isn't there! Baffling. At the same time, if you were to ask him about the latest news or sports he would be able to talk about it for hours!