Why does helium make voices sound funny?

Answer: Sound travels faster in helium

Gas pressure squeezes the throat — Wrong. Gas pressure isn't what changes your voice. It's the speed of sound in helium versus air that creates the high-pitched effect.

Sound travels faster in helium ✓ — Correct! Sound travels nearly 3 times faster in helium than in air. This increases the resonant frequencies in your vocal tract, making your voice sound higher-pitched. Your vocal cords vibrate the same, but the sound quality changes.

Helium chemically changes voice box — Wrong. Helium is inert and doesn't react chemically with your body. The effect is purely physical—sound waves move faster through helium.