Welsh isel

← Proto-Celtic *ɸīsselos (inherited)

← Proto-Celtic *ɸīssu (mention)

← Proto-Indo-European (derived)

← Proto-Indo-European *pṓds (mention)

← Old Irish ísel (cognate)

← Middle Welsh isel (inherited)

→ Welsh isod (mention)

→ Welsh penisel (affix)

→ Welsh iselydd (suffix)

→ Welsh iselder (suffix)

→ Old Irish ísel (cognate)