This sentence could be talking about food, right? But if I saw the English translation without context I'd think it was about a book. Could you use sűrű to talk about a dense book, too?
Talking about a person? :)
Yes, "sűrű" can be translated as both "dense" and "thick". But only in the density sense.
For thickness that can be measured with a ruler, use "vastag".
I don't hear anything like that. But it might be. You can never really isolate all the sounds you speak. :)