Final answer:
The figure of speech in the line "Her laughter cuts the soul of the listener" is a metaphor, implying that the laughter has a deep, emotional impact on the listener.
Step-by-step explanation:
The figure of speech in the line "Her laughter cuts the soul of the listener" is a metaphor. A metaphor is a direct comparison between two unlike things for rhetorical effect without using "like" or "as". In the sentence given, laughter, which is usually a sound, is being compared to a sharp object that can actually cut, which it literally cannot do. This metaphor suggests that the laughter is so piercing or affecting that it deeply impacts the listener's emotional state.