https://www.thesaurus.com/e/grammar/whycapitali/#:~:text=For a long time%2C it,is intended to stand alone.
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Reasons why I is always capitalized
Hard to believe, but there were no rules for capitalization until the 1700s. For a long time, it was common to mix lowercase and capital letters within a word, the latter used to add emphasis. Historians now attribute the capitalization of I as a result of two factors:
The lowercase i is difficult to read: By capitalizing I, it makes it more clear that the letter is intended to stand alone.
An uppercase I symbolizes importance of the writer: The I has retained the capitalization because it also gives added weight to this pronoun used to describe the individual writer. Some languages do capitalize different pronouns,"