Our memory of exact word sequences usually fades more quickly than our memory of (contextually interpreted) meanings.
More broadly, the exact auditory sensations normally fade very quickly; the corresponding word sequences fade a bit more slowly; and the interpreted meanings last longest.
These generalizations can be overcome to some extent if the sound or the text has especially memorable characteristics. (And the question of what "memorable" means in this context is interesting.)
I worked for several years as a leader of birding tours, and I have met a few sad individuals who were so focused on adding to their life lists that they would refuse to look at a bird species that they had seen before, no matter how spectacular the view or how fascinating its behavior of the moment might be. “I don’t need that bird” was their standard reply.
For a person just getting started in some area of natural history, and unabashed focus on list-chasing is a good thing, at least for a while. The trick is knowing when to stop.
Keith Brown described how he got the idea “that the maximization of daily species lists of butterflies, a seemingly unscientific goal (though much employed in a sister area, ornithology), could give a large scientific fallout."
For example, he described how six weeks’ effort in the Brazilian central plateau had turned up twenty-five species previously unknown for the area—but then he had adopted the “maximization” method, and in another six weeks, he had found nearly three hundred more species.