Why are German pronouns "sie" (feminine singular third person) and "Sie" (plural third person) morphologically identical, regardless of the capital S?

Answer 1

Though there is no exact answer to why "Sie" and "sie" are lexically similar but semantically different, one thing to consider is the etymological history of pronouns across Germanic languages. German possesses the 3rd person plural pronoun "Ihr" and, in certain dialects of German, the pronoun can be used as a 2nd person plural. In the case of "Sie/sie," the most plausible influence can be attributed to formality. Historically, "Er" and "Sie" could both be used for formal address. German speakers likely increased formality by pluralizing, changing person (from 2nd to 3rd), and capitalizing: du -> sie -> Sie. For examples in other germanic languages, "you" in English can be 2nd person singular or plural, and Swedish "Ni/ni" and Danish "de/De" can be singular or plural as well.