Adam Clarke on Nehemiah 13:24

Half in the speech of Ashdod - There were children in the same family by Jewish and Philistine mothers. As the Jewish mother would always speak to her children in Hebrew or Chaldee, so they learnt to speak these languages; and as the Ashdod mother would always speak to her children in the Ashdod language, so they learnt that tongue. Thus there were, in the same family, children who could not understand each other; half, or one part, speaking one language, and the other part another. Children of different wives did not ordinarily mingle together; and the wives had separate apartments. This is a better explanation than that which intimates that the same child spoke a jargon, half Ashdod and half Hebrew.