It’s pretty simple to start at the fact you have a species that can read the thoughts of other people, even outside their species, and even inject thoughts into those other beings minds. So there must be something detectable that sentient species emit that can be detected and understood, and can also be pushed at them. Once that mechanism’s understood, a machine can be developed to apply that to language. Sato is really good at using that machine.

Of course “magic box” works too.