"PIIIKACHUUUUUU!" Pikachu shot out lightning and shot forward to Staravia.

While Ash was healing the bird Pokémon, Pikachu's ears twitched and looked at a pair of bushes nearby. "Pika?" Pikachu approached the bushes without Ash or the others noticing and stuck his head through them. His eyes widened to what he was seeing.

"Pika! Pika!" Pikachu said pointing at the nearby bush. (maybe sound worried. and I guess if you want since these are only a few examples of lines pikachu does in the story try out for pikachu with other emotions doesn't matter what you say for now)