According to Merriam-Webster, it arrived in English in th 1930s, from Yiddish: Merriam-Webster's definition of "lox": http://www.merriam-webster.com/dictionary

According to Merriam-Webster, it arrived in English in th 1930s, from Yiddish: Merriam-Webster's definition of "lox": http://www.merriam-webster.com/dictionary/lox http://www.merriam-webster.com/dictionary/lox Corroborated by the OED: https://www.etymonline.com/word/lox https://www.etymonline.com/word/lox (exact year conflicts; 39 and 34, resp.) Given the excerpt of the original article (404) from your link, I'd guess the word traces back that far linguistically, and is more or less unmodified in sound, even though it only arrived in English recently.