Noun
:The organization of all the tones and harmonies of a piece of music in relation to a tonic.
https://www.merriam-webster.com/dictionary/tonality
In the article, “An avatar analysis: Choosing your profile picture” Chad uses it in the first sentence in the first paragraph, “In the digital space, we do not have the luxury of forming an opinion based on body language, tonality, or other non-verbal forms of visual communication.”
Chad meant that people only form opinions on verbal forms of communication, and not non-verbal