How does the author’s use of diction contribute to the mood of the excerpt?

The factual description of “How different my two aunts are” creates a somber mood.
The formal descriptions of “Obasan’s language” and “Aunt Emily, BA, MA” create an uplifting mood.
The vague description of “One lives in sound, the other in stone” creates a confused mood.
The playful descriptions of “word warrior” and “gray-haired Mighty Mouse” create a lighthearted mood.