As many Greeks will tell you, the Greek language is a very rich language and when a native speaker is in action, it is often also accompanied by a rich variety of facial and hand gestures. These serve, both consciously and unconsciously, to give emphasis to that which is being said, or can be used on their own as a non-verbal response.
Greeks do not usually shake their heads from side to side to indicate a negative response ie "no". Instead they tilt the head upwards and backwards, and then back down to looking directly ahead. This is done only once. This should not be mistaken for a nodding of the head meaning "yes". Sometimes the tilting of the head is accompanied by an audible click of the tongue against the teeth. There are also variations on this. For emphasis, meaning something like "no, of course not" or "no, you're way off the mark" the head may be tilted up and back in a very slow deliberate movement sometimes with a partial or full closing of the eyes. On other occasions, the whole movement can be reduced to a very slight and quick raising of the eyebrows. This can be very hard to detect, therefore leading you to ask your question repeatedly to that person until the movement becomes more perceptible or they lose patience with you and actually tell you their answer. Non-verbal responses can be surprisingly powerful and can elicit an interesting reaction from a foreigner who is not used to it. For example, you may think that the slow deliberate "no" movement indicates that your listener believes what you have said or suggested to be completely ridiculous and not worthy of a verbal response – you would be mistaken.
For "yes", the head is tilted downwards and slightly to one side. As with "no", this is done only once. Again, this can be done slowly and deliberately for added emphasis.
Shaking the head
As we have seen this does not mean "no". It serves to indicate that someone does not understand what is being said to them or alternatively, the reason it is being said. This is sometimes accompanied by an extension of the hand outwards with palm facing down to the floor and then rotating it, with the thumb and first two fingers extended, until the palm is facing up.
Impolite and vulgar hand gestures
Come on, I have to cover at least one or two. As in many countries, there are impolite and vulgar hand gestures that are more expressive than any words in certain situations. The Greeks have an expression which literally translated means "I am writing you on my testicles" !. This actually means "I am totally ignoring what you are saying". It would take too long to go into the many Greek sayings, but I have also heard an interesting variation on this one uttered by a woman, which goes "I am going to grow testicles just so I can write you on them"! Anyway, the related hand gesture, which is often used alone without the expression, is a swift movement of both hands downwards, palms facing up, and fingertips almost touching forming a v-shape over the stomach, as if indicating the location of the genitalia . Finally, another hand gesture which is a rude way of telling someone to "go away" (I'll let you use your imagination and creative talent), is to extend your arm in the direction of your target with a closed fist. Then as the arm is fully extended, the fingers are spread widely revealingly the palm at a 45-degree angle to the ground. It is done in one movement and is similar to the action of throwing a ball. This is probably most frequently seen on the road between drivers. However, this will be considered a strong insult if used on a stranger, so be prepared to deal with literally any consequences before resorting to it!