* "Whistle" - This is the most common and straightforward spelling.
* "Whee" - This is a short, sharp sound often used to represent a quick whistle.
* "Woo" - This is a longer, more drawn-out sound often used for a whistle with a higher pitch.
* "Whew" - This spelling is often used to represent a whistle that expresses relief or surprise.
* "Shhh" - This spelling is used for a soft, quiet whistle.
Ultimately, the best way to spell the sound of a whistle depends on the context and the desired effect.