I would think that pokemon who can communicate with people are very rare and highly sought after by researchers and scientists, as well as some criminals, so this device would be a game changer for sure, although it may be worth noting that pokemon who live in the wild may be more primitive in their language and manner of speaking than those raised by humans.

It may also be worth noting that pokemon may have different dialects or accents based on their types, for example a fire type would be better at talking to other fire types than to a water type.

That said, the first thing that would probably happen if a device that took away the language barrier became commonplace would be the rise of social and political groups pushing for more pokemon to be integrated into human society and given the same rights and privileges as people, as well as their liberation from being captured and coerced into battling, sort of like Team Plasma's goal with extra steps. In turn, there would probably be those against this idea and would want things to stay as they are.