Question: What is sub-text? Someone said mine was "unclear?" Huh?
Answer: Subtext is what the reader understands from what is said, though it isn't really said.
Sounds a bit difficult, I know. But we all hear it and understand it every day. Usually, in dialogue, it's what the reader infers from what the character has said.
In dialogue and narrative both there is always both text and subtext. First there is what is said, and second what is implied by what is left unsaid. Often, subtext, which the reader picks up on, is as important as what is actually said. Look at the following:
“Oh, is that slide show at the library with the nature photographer tonight?” John grimaced. “I’ll go if you want, but I’m really tired. After all, I was out to the Bible Study at church last night and you stayed home and read. This makes two nights in a row, for me. Of course, I don’t like to mess up your plans....”
Sounds like a nice husband trying to be understanding, right?
Of course he wants to mess up her plans. If he didn’t, he’d say, “You go ahead, hon; I’m too tired tonight. The subtext of the above dialogue is, “You couldn’t find time to go with me last night, so I’m NOT going to be nice about what you want to do tonight.”
The reader understands that the husband is being crappy on purpose and so does the wife. Though she can't very well say so, out loud.