Joyful laughter, cheerful sounds, or merry tunes can serve as antonyms for the phrase "plaintive cries." Where plaintive cries connote sadness, lamentation, and mourning, their opposite signifies happiness, delight, and pleasure. Antonyms bring balance to our language by providing contrasting ideas to words that may have a one-sided interpretation. In literature, juxtaposing antonyms like "plaintive cries" and "joyful laughter" can add depth and complexity to a scene, highlighting the shift in mood, tone, or emotion. As opposites attract, antonyms can also make our language more engaging, exciting, and dynamic, creating a rich tapestry of meaning and expression.