Voices cannot be generated in vanilla Minecraft. They are custom sounds added by mods.
All the commands you tried are for printing messages in the chat.
/playsound is the only command that can play sounds, and it can only play predefined sounds. You will need to add your own voice as a custom sound using add-ons.
I'm not much of an expert in modding Minecraft, so I'm not the right person to ask for the job. Check out info on add-ons if you want to explore this path further, or you can wait for the next answer from a more experienced Minecraft modder.