Where does “Ершалаим” come from?

Ершалаим (Russian) comes from Hebrew יְרוּשָׁלַיִם — Jerusalem.

Ancestry of “Ершалаим”, step by step

Step	Language	Word	Meaning
1	Hebrew	יְרוּשָׁלַיִם	Jerusalem

Ершалаим — Etymology, Origin & Word History | Etymology Explorer