Venenum

The second declension neuter Latin noun venenum originated Portuguese and Spanish veneno, French and Romanian venin, English venom and two strange forms: Catalan verí and Italian veleno (Italian also has veneno, but it's described as poetical in dictionaries). It's interesting that the original n transformed into other consonants in the two last mentioned languages. I understand that the second n in Italian veneno caused dissimilation, meaning that it affected the previous consonant, which is also an n, but why an l was chosen instead is beyond my comprehension. A similar phenomenon could be used to explain Catalan verí, which was probably verin and earlier venin centuries ago, and since Catalan is not so fond of final nasal consonants, that n, before it caused the dissimilation of the first n, was eliminated. What I can see is that both l in Italian veleno and r in Catalan verí are liquid consonants, so maybe that would be the beginning of a possible explanation for the current state of things.