One of the first things I noticed about my wife's behaviour when we first started to date was her constant spitting.
We would be walking in a shopping centre and she would frequently walk up to a bin and spit.
When walking on a public street, she would at times spit on the street.
This is not something particular to her alone, it is in fact quite common amongst the Chinese. This need to spit repeatedly is so common in China that the Chinese government had gone to great lengths prior to the Beijing Olympics to re-educate the Chinese against spitting in public.
So why do they do it?
I can't be certain.
It could be argued that its a reaction to the extreme air pollution in some Chinese cities, however my wife left China before it really began to industrialise with a vigour, and she herself has never experienced high levels of air pollution.
I would add that the spitting continues day and night, inside the house and out.
Although as a Westerner I find this practice quite distasteful, I have simply learned to ignore it when it comes to my wife. I have even learned to get used to the two or three times during our love making that she will stop, run to the bathroom, spit, and then come back.
But what I find disturbing is that now my son is starting this habit as well. There are times when I am simply having a conversation with him, and while talking I can hear him making a strange noise in his throat.
This strange shrilling noise is a common pre-cursor to the spit, and not long after, my son runs to the bathroom to spit in the toilet.
When I ask him why he does it, he explains that he doesn't know.
My wife did make a comment once that she considered mucous to be unhygenic and bad for the body, and so she prefers to spit it out rather than swallow it. Maybe its something as simple as that. We as Westerners simply clear our throat by swallowing, whereas the Chinese clear their throats by spitting.