They look very cute. I especially like the effect of the orange on Chirple's beak making it look a bit silly. As for the additional things to say, they can say "It's not over yet" or "It's time to get serious" when their HP gets low [That's what Megaman and Zero say in a game.]. They can also "Too fast/slow" when they attack first, "Run away" when running away/surrendering, and "Take that" on crits. They can probably give hints on whether their attack was effective/not effective against an opponent; "This isn't working" or "That's gotta hurt". When summoned, they can say "Let me at 'em". There are a lot of possibilities, especially when beating an enemy; "Got 'em", "Booyah", "I'm the best", etc.
That was just if the Chirple personality was angsty or rugged. You can also go kind of formal/majestic with Chirpily. Lots of Warcraft 2 unit sounds come to mind. "Your orders?" "By your command".
haha good ones!