The main point of the keyword phrase is the noun "birthdays." In this construction, "birthdays" serves as the head noun, which is the central element that the other words in the phrase modify and describe.
A grammatical analysis reveals that "september 11th" and "anime" function as adjectival modifiers. "Anime" is a noun used attributively to specify the category of the birthdays (i.e., those belonging to anime characters). "September 11th" is a compound modifier, composed of a noun and an ordinal number, that specifies the exact date of these events. Together, these modifiers narrow the scope of the head noun, defining a highly specific topic: a list or discussion of birthdays of anime characters that occur on a particular date.
Understanding that "birthdays" is the core noun is crucial for content creation. It establishes that the article's primary purpose is informational and descriptive, centered on presenting a collection of facts (the characters and their associated series). The adjectival modifiers dictate the specific parameters of this information, ensuring the article remains focused on the precise intersection of anime culture and the calendar date of September 11th. The structure of the article should therefore be a list or exposition of these specific birthdays.
