Some singers, like Joseph Taylor, appear to have used a higher than speaking voice. The training of an operatic coloratura soprano basically involves learning to sing falsetto which destabilises the voice and allows much quicker movements over the tonal range. This means that decoration and embellishment can be performed more easily that with a 'speaking' range voice. I sometimes wonder whether Taylor knew that, by using the top of his range, he would have similar access to faster and easier ornamentation? Interestingly, Taylor is not unique among traditional singers for using this device.