Tone of voice is an organisation's deliberately chosen way of sounding – and at a time when AI can imitate any style, the voice is a strategic choice, not decoration.
As long as people wrote all the text, the voice emerged by itself – as the sum of those people's language. Now a language model can write formally, playfully, authoritatively or warmly on command. Style has become a setting you choose.
That creates a new requirement: if you have not described how you sound, the machine chooses for you – and it chooses the average. A written tone of voice is therefore no longer a nice document in a drawer, but a management tool for all AI-assisted text.
In practice
A tone of voice guide that is concrete enough to be part of a prompt – words you use, words you avoid, before-and-after examples – means that newsletters, press releases and LinkedIn posts sound like you, regardless of who or what wrote the first draft.
»When the machine can imitate every style, our voice is a decision – it has to be described, or the AI will make it for us.«
I have unfolded why the voice is strategy and not decoration in the article Tone of voice is not decoration.