English buttermilk

← German Buttermilch (cognate)

← English butter (affix)

← English milk (affix)

← Middle English butter-melke (inherited)

← German Low German Bottermelk (cognate)

→ English buttermilky (suffix)

→ Faroese blak (link)

→ Japanese バターミルク (borrowed)

→ Korean 버터밀크 (borrowed)