How and why did English lose "thou"

In EmE, there were 2 distinct pronouns that translate to "you" in Modern
English: thou, used in the singular; and ye, used in the plural/formal
singular. This is a common distinction in other languages (Spanish, German,
French, etc.), so how come "thou" was lost?

It was useful to be able to distinguish between the 2nd person singular and
plural. Useful enough that "y'all" has become a recent replacement for "ye"
in some informal dialects.


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