Helloo !
I don't know if this will help you but here's how I did it.
In PhoneTexting : define MC_Name = "Me".
Then in script : define n = Character("[name]", image="mc", color="#0e7a38")
define n_nvl = Character("Me", kind=nvl, image="mc", callback=Phone_SendSound)
It doesn't mark the MC name, but it's on the sender's side.