Welsh gwylan

← Breton gouelan (cognate)

← Proto-Brythonic *gwuɨlann (inherited)

← Proto-Celtic *wailannā (inherited)

← Irish faoileán (cognate)

← Cornish goolan (cognate)

→ English gull (cognate)

→ English seagull (cognate)

→ Cornish goolan (cognate)

→ Middle Irish faílenn (cognate)