brett said if a new federal government decided to withdraw the workforce supplement funding after the first year dpg had agreed to fund a 3 % increase in the second and third years of the agreement
Pure helium is a medium that allows sound to pass through it more quickly than air, so it makes your voice sound higher pitched (the mechanics are similar to speeding up a video and hearing the sound pitch up). Some gases will do the opposite; most commonly, sulfur hexaflouride, which slows down sound waves.
If you replace the air (Nitrogen-Oxygen mix) with something LESS dense like Helium (1/6th the density of air) then the sounds made by the vocal chords working exactly the same as they did in air, will have a higher apparent pitch because the sonds they make move faster through helium than they do through air.