Based on the example ᴹ✶besnō > Ilk. benn (Ety/BES), it seems that [sn] became [nn] in Ilkorin, as was also the case in Old Noldorin. It is unclear whether such assimilation also occurred for [s] followed by [m], [l] and [r], as happened in Welsh (WGHC/§95ii) and Old Noldorin.