Answer:
"ankle on knee, hands together in the lap "
Step-by-step explanation:
Simply put, an unusual language can be the type of language that is not normally used in a conversation or speech. It can be a weird way of saying things or even a different structuring of the words in a sentence that seems to mean something other than the intended one.
From the given excerpt of David Foster Wallace's "Infinite Jest", the example of an unusual language is the use of the words "ankle on knee, together in the lap". This sounds weird in itself, considering the sentence frame. How can the ankle be on the knee and both hands together in the lap? But though it sounds weird, it is just the description of how the character was sitting in front of the others.
Thus, the correct answer is the first option.