What do we call the personality of the author expressed through word choice and style?

The personality of the author expressed through their word choice and writing style is referred to as voice. This concept encompasses the unique tonal qualities, diction, and perspective that an author employs, which can convey their individual style and influence the reader's perception of the text. Voice plays a crucial role in helping to establish connections between the author and the audience, making their work distinctive and engaging.

In contrast, the other options do not accurately capture this specific concept. "Phrase" refers to a small group of words that express a particular idea, rather than the broader characteristic of an author's overall style and personality. "Character" typically relates to the individuals in a narrative or text, whereas "theme" pertains to the underlying message or central idea within a piece of writing. Therefore, voice is the most fitting term to describe how an author's personality is manifested through their writing.