My theory is that the Pokemon spoke their names naturally.
Given that many names of Pokemon are a mix of actual words, it is possible that the human language of the Pokemon World has roots in the Pokemon language.
Not unlike how English is derived from German or Italian deriving from Latin.
This is an interesting theory. It's like the one that posits that Pokemon who appear to be wearing human clothes are actually not- rather, humans made clothes fashioned after the Pokemon themselves. For example, Hitmonchan inspired the creation of boxing gloves, and the Karate gi was fashioned after those worn by Sawk and Throh.
Scrafty would have also inspired the punk youth subculture rather than the other way around, and Conkeldurr taught us to use concrete (this last one is actually supported by a Pokedex entry). Basically, it's the theory that in the Pokemon world, anything that looks human-made on a Pokemon's design was actually a natural thing that humans ended up borrowing from.