The primary part of speech for the keyword phrase "national read a book day activities" is a noun. The head noun, and therefore the main point of the phrase, is "activities." The preceding words, "national read a book day," function collectively as a compound adjective or noun adjunct, specifying the type of activities being discussed.
In this grammatical structure, "activities" is the core subject being modified. The phrase "national read a book day" acts as a single descriptive unit that answers the question, "What kind of activities?" This multi-word modifier narrows the focus from general activities to a specific set related to the observance of National Read a Book Day. The analysis involves identifying the core element ("activities") that carries the primary meaning, while the other words provide context and specification.
This determination is crucial for content creation because it establishes that the article's primary focus must be on the actions, events, and undertakings themselves. The content should be structured to list, describe, and explain various things one can do to celebrate the day. The phrase "national read a book day" sets the theme, but "activities" is the operational subject that the article must deliver on.