The original poster started a very interesting discussion about using language that might be misunderstood by children, and I am reposting my comment because I would like to share my viewpoint with my readers.
I can appreciate your concern for your students, (e, but I agree with MM. Although some ways of communicating may be confusing, I believe they should be taught rather than avoided. Each instance of misunderstood sarcasm can be a teaching moment for a second language learner. Sarcasm and other elements of second language, which English is for most deaf and hard-of-hearing people, have to be explicitly taught.
I sometimes have to reverse myself when I begin to — forgive the expression — “dumb down” my writing with deaf people. With certain people, things must be greatly simplified, but with many people I think one should be oneself and let the person figure it out. Most deaf people certainly don’t dumb down their ASL for me or slow down their signing for me. I am an interpreter, and they just expect me to understand them and interpret what they are saying. I learn new bits of visual language all the time because of deaf people’s being themselves and signing naturally. Don’t I owe them the same genuineness of myself? Perhaps the more I write English or — with the appropriate person — sign English or fingerspell unusual turns of phrase, the more I express who I am and give them the opportunity to learn how a hearing person speaks and writes.
It’s not that my place is to teach; it’s just that everyone–hearing and deaf alike–can learn more about each other and each other’s language when we speak naturally. I thank every French-speaking, Spanish-speaking, and ASL-speaking person who has ever spoken to me in their natural way, because that is how I have learned their languages.