You don't need to say " Watakushi wa." Watakushi is a formal form for "I." We don't use that word for a casual conversation. In Japanese we omit a subject in casual conversations so we just use a verb and an adjective such as " am hungry (Onaka Suita or Onaka ga suita) " Maybe that doesn't make sense to Americans but that's just the way we speak.
Anyway, there are several ways to say " I'm hungry" in Japanese. If you are a man, you can say " Hara hetta" or " Hara ga hetta. These are kinda musculine ways to say the phrase. But you can always say " Onaka suita" or " Onaka ga suita " because both men and women use that phrase but usually more women say that. But if women say " Hara hetta" or " Hara ga hetta," people would think that she doesn't speak like how women should speak.
By the way, a formal way of saying this is " (Watashi ha )Onaka ga suiteimasu." If you are doing some homework for some college textbook, use this phrase, instead.
Anyway, I hope this helps.
· 9 years ago