Here you can found many words and animations, made up by the best experts in string theory and by using of million dollars of financial support.... Isn't it enough?
The fundamental assumptions of string theory are solely abstract, so they cannot be explained by using of string theory, only by some other, more general one. For example, the 1D strings and 2D branes are counterparts of density fluctuations of inertial environment, composed from dense particles recursively, but such explanation has nothing to do with string theory as such and it doesn't explains, what the string theory is all about. By the string theory proponents such explanation is quite unmotivated, so it's evident, the string theory has nothing to do with Aether.