Negating a statement means that the proposition of an utterance is not to be true. A clause can be negated by means of negation such as negative headshakes.

In Austrian Sign Language a proposition can be negated manually and/or non-manually. Manual means of negation are negative signs as shown by the following examples:
“S/he has not said anything.” (NOT-YET)
“S/he has not come.” (NOT or NO)
“S/he does not believe/think (that).” (NO or MUST-NOT)

Non-manual means of negation are headshakes which can negate a proposition without any negation signs (as described above). In “s/he does not sign”, “s/he does not understand”, and “s/he does not come” the propositions are only negated by negative headshakes.
Current findings in ÖGS show that in natural discourse such as monologues, dialogues, signed lines of thoughts headshakes frequently occur, if a clause is to be negated. For example, the clauses “I do not require help” or “there is no communication” are negated by negative headshakes. Negative headshakes can co-occur with the entire clause (such as in “I have not yet written the offer”) or with a part of the clause (such as in “the boss has not informed me” or “the person has not answered”). In the latter, in most instances in the data negative headshakes co-occur with the verb and negation sign. What is more, the data show that negative questions (such as “Don’t you understand?” or “Has the person not answered?”) and negated if-clauses in conditionals (such as “If I don’t have to work, I will go on holiday.”) tend to be accompanied as a whole by negative headshakes. (The clauses which are underlined are accompanied by headshakes.)