Salmon
Middle English samoun, from Anglo-Norman French saumoun, from Latin salmo, salmon- . The spelling with -l- is influenced by Latin.
wiktionary
From Middle English samoun, samon, saumon, from Anglo-Norman saumon, from Old French saumon, from Latin salmō, salmōn-. Displaced native Middle English lax, from Old English leax. The unpronounced l was later inserted to make the word appear closer to its Latin root (compare words like debt, indict, receipt, island for the same spelling Latinizations).
etymonline
salmon (n.)
early 13c., from Anglo-French samoun, Old French salmun (Modern French saumon), from Latin salmonem (nominative salmo) "a salmon," probably originally "leaper," from salire "to leap" (see salient (adj.)), though some dismiss this as folk etymology. Another theory traces it to Celtic. Replaced Old English læx, from PIE *lax, the more usual word for the fish (see lox). In reference to a color, from 1786.
