Welsh tu

← Breton tu (cognate)

← Proto-Brythonic *tʉβ (inherited)

← Proto-Celtic *toibos (inherited)

← Irish taobh (cognate)

← Cornish tu (cognate)

← Old Irish táeb (cognate)

→ Welsh tua (compound)

→ Welsh tudalen (compound)

→ Welsh tuedd (affix)

→ Welsh neilltu (compound)

→ Old Irish táeb (cognate)