This may be odd, but I prefer both at once. For example, a Fletchling saying its name, but also being able to chirp, due to its cry in the anime and its Pokédex entry that describes its "lilting chirps." I believe that Pokémon were named after what they said repeatedly, but they can also utter basic animal sounds. The names add so much more personality to their speech, I feel like it's a necessity, and their animal noises are great, too!