LIS is a visual language and for this reason it is quite different from the spoken languages.
Speaking people use the voice's intonation to express and, according to intonation, the same sentence can have difference meaning.
Persons who use signs, instead of modulating their voice, express themselves:
- with hands,
- with face expressions,
- with body posture.

In the examples presented in the next page, you can see how face expression changes when one asks a "open" question or a "closed" question.

So, for the person who use the signs, it is possible to express emotions and in the same time to complete a grammar function: the question form.