[ilfzfirb] Shoybean

"Soy" is a loanword, from the Japanese word shoyu meaning soy sauce.  (The Japanese word for soy bean is daizu.)  When did the shift from "s" to "sh" occur?  Both sounds are present in both Japanese and English.  Wikipedia says the word came to English from German "soja", which still begs the same question.  German also has both the "s" and "sh" (spelled sch) sounds.  It is possible the consonant shifted in Japanese.

Consider pronouncing the English word as "shoybean" as the pedantically more correct pronunciation.  Similarly, calling soy sauce just "soy" (heard elsewhere) pedantically has merit: soy sauce is redundant like Mount Fuji-san.