An author's tone refers to their attitude toward the subject. It reflects how the author feels about the topic they are writing about, which can be conveyed through word choice, style, and emotional language. Tone can be formal, informal, sarcastic, serious, playful, and more, and it significantly influences the reader's experience.
In contrast, the way they build suspense relates to narrative techniques that create tension and anticipation, their purpose for writing encompasses the reason behind the text (to inform, entertain, persuade, etc.), and dialect pertains to the particular form of language used by characters, which can reflect their background or region.