Middle names are a weird custom.
It's like a semi-secret part of your name that you only randomly use sometimes, and usually only in initials, and which no one else knows except your family.
It is as if the Anglo-Saxons were preparing for a real world Death Note attack I know your true name-style.
Many East Asians, notably Chinese immigrants, choose to adopt a Western name pseudonym to make it easier for Western people who don't speak the language to call them and remember their name.
Cowards! Ciro Santilli would much rather just torture foreigners into learning his language. But fair play.
More interestingly however, some of the names chosen are not typical names, and some end up being very cute or mildly funny. Perhaps it is partly linked to given names are getting weirder.
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A noun is a part of speech whose members commonly name entities or concepts and head noun phrases. Meanings alone do not supply a complete classification: a noun can name an event or property as readily as a physical object. Distribution and inflection provide additional grammatical evidence.[ref]
Universal Dependencies annotation guidelines. NOUN, Definition and examples including abstract nouns
For example,
explosion names an event, but behaves as a noun in the explosion and two explosions. Its connection with an event does not make it a verb; compare The shell exploded. Likewise, redness is a noun even though it names a property associated with the adjective red.In Universal Dependencies, the tag
NOUN is reserved for common nouns, with PROPN used for proper nouns. That distinction matters when reproducing an analysis: a count of every traditionally named noun is not necessarily a count of only tokens tagged NOUN.