With verse 19 the narrator pauses and gives some information about Lamech and his sons.

Lamech took two wives is the first mention of a man having more than one wife. Wives is a form of the same word for wife used in 2.24, 25. The meaning of Adah in uncertain. Zillah means “shade or shadow.” The same noun occurs in Isa 32.2. Took two wives does not say whether he took both at the same time or separately. In some languages to marry plural wives is a special term. Often the various wives are known by special terms; for example, “The name of the head wife was Adah, and the name of the small wife was Zillah.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .