1.8 is a version from 2014, I'm not even sure if Mojang would still have the source code for that. (I know Decomps are easy to make, but Mojang might not be willing to go through all of the trouble of going through all of that to update a version that itself has been out of date for about seven years...)
Far
Not sure if you care, but there are plenty of mods that add it.
https://www.curseforge.com/minecraft/mc-mods/sound-subtitle-port-1-8/files
https://www.youtube.com/watch?v=yZSTqAVAuqc
1.8 is a version from 2014, I'm not even sure if Mojang would still have the source code for that. (I know Decomps are easy to make, but Mojang might not be willing to go through all of the trouble of going through all of that to update a version that itself has been out of date for about seven years...)