> I can't use "else" as a conjunction in normal speech, only in computer programs.

Not true. Here's an example from 1876 in which "else" is used as a conjunction.

> My brother is poor, and I want to look as much like him as I can, else he may feel distant from me.

-- George Eliot ( https://www.victorianlondon.org/etexts/eliot/deronda-0047.sh... )

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Here's an example of "if ... else" from the 1914 translation of Crime and Punishment ( https://en.wikisource.org/wiki/Crime_and_Punishment/Part_IV/... ):

> Perhaps it will all come back, but now if you love me, give me up . . . else I shall begin to hate you, I feel it.

1611 Psalm 51:16 (KJV) uses else as a conjunction as well.