The phrase "I'm hungry" in Japanese can be expressed in several ways depending on the level of formality and tone. The most common and polite way is お腹がすいた (onaka ga suita), which literally means "my stomach is empty." In casual conversation, you can shorten it to お腹すいた (onaka suita) for a simpler and more relaxed expression. For very informal or slangy contexts, 腹減った (hara hetta), meaning "my belly is empty," is often used, especially among men or close friends. Another playful or childlike way to express hunger is お腹ペコペコ (onaka peko peko), using the onomatopoeic word ペコペコ (peko peko) to mimic the sound of a growling stomach. These variations allow you to adjust your tone based on the situation, making it easy to let others know you're ready for a meal!