There is no such thing as "mixed nodes". I think your difficulty is related to the case where you have the node
"in the middle of other text". In fact, there is no such thing. From the DOM standpoint, the actual hierarchy looks like this:
Text node: "word text "
Text node: "first name"
Text node: "word text"
Are you getting the idea? There is no any "mixed" nodes here. Instead of having a text node with some content in the middle, you have two separate ones. I hope it will help you.