Is there a way to extract files from Oblivion.esm? I want to extract some sound files that are within Oblivion.esm, but I can't seem to find a program that does such an extraction.

The closest I could get to was opening the dialogue window of NPCs in TES Construction Set, and seeing which dialogue goes with which sound file and the directories (inside Oblivion.esm) in which the sound files are located.

???

I am not aware of any sound files contained in Oblivion.esm. There are several sound files (packed as .bsa files, as are all Bethsda's files) in the Oblivion directory, though. These packed files include voices (specifically, Oblivion - Voices1.bsa and Voices2.bsa). There are .bsa viewers and extractors on community sites such as TES Nexus.