Making short, high-pitched sounds like birds do, or the sound itself made by birds or insects.
From Middle English 'chirpen,' likely from Old English roots related to imitative sound-making. The word is onomatopoetic, meaning it imitates the actual sound that birds and insects produce.
Chirping is one of the few words that actually SOUNDS like what it means—when you say 'chirp,' you're kind of making a little chirping sound yourself, which is why kids and animals respond to the word almost instinctively.
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