needing shorter slugs or menu options

We’ve been moving our site into wordpress. Need to use parent and child pages three to four levels deep for our navigation system, so that the menus’ for our books display properly. However, extremely annoyed to see that word press includes the slugs for every parent page in the file name, making for extremely long URL addresses. Searched the codex and looked for plugins, but can’t seem to find how to address this issue. Does anyone know of a plugin or a way to edit the .HTA access file so that we can remove/altar this to customize slugs?