Factor analysis (principal component analysis followed by varimax rotation) had shown that three common factors appear across 20 critical-band power fluctuations derived from spoken sentences of eight different languages/dialects [Ueda et al. (2010). Fechner Day 2010. Padua. https://www.spidertattooz.com/The-GelBottle-Inc-BIAB-Gel-Polish-Spirited-67oz-p17706/