Endeth this nonsense
The reason you can hear them is because, if you look at chat log, they arent speaking common, or any other specified language, therefore they are not scrambled towards any race or faction. if the NPCs in chat had "Jain proudmoore says: [COMMON] bla bla bla"
You wouldnt be able to read, but honor hold mobs and many others around azeroth d not speak common or orcish, but a neutral language as you can see from chat. therefore they are not translated.
man i ussually dont type posts this long.