1) the mouth must be shaped to pronounce "R" at all times. 2) The last vowel of most words the Stapp Speaker uses must be substituted with "errah", "err", or "eeya". Translated into Stapp Speak: Therrah lerrast vowerrl errahf merahst werrahds therrah Sterrahp Speakerrah userrahs merrust berrah substituterrahed with "errah", "err", or "eeya". This rule may be omitted to certain words by the Stapp Speaker's own judgment. 3) When all else fails, just make it sound stupid.
Singing in this voice can at worst lead to vocal damage and at best make everyone hate your band.