Tourettes Syndrome is :

"I'll promise to stop twitching, if you promise to never sneeze again."          anonymous

Tourette Syndrome (TS) is a neurological disorder characterized by tics -- involuntary, rapid, sudden movements or vocalizations that occur repeatedly in the same way.

Diagnostic criteria include:
Both multiple motor and one or more vocal tics present at some time, although not necessarily simultaneously;

The occurrence of tics many times a day (usually in bouts) nearly every day or intermittently throughout the span of more than one year;

Periodic changes in the number, frequency, type and location of the tics, and in the waxing and waning of their severity. Symptoms can sometimes disappear for weeks or months at a time;

Onset before the age of 18.

Although the word "involuntary" is used to describe the nature of the tics, this is not entirely accurate. It would not be true to say that people with TS have absolutely no control over their tics, as though it was some type of spasm; rather, a more appropriate term would be "compelling."  People with TS feel an irresistible urge to perform their tics, much like the need to scratch a mosquito bite. Some people with TS are able to hold back their tics for up to hours at a time, but this only leads to a stronger outburst of tics once they are finally allowed to be expressed.

Although the DSM-IV has recently changed the upper age of onset from 21 down to 18, the Tourette Syndrome Association Medical Advisory Board is working to have it reverted back to 21, as is listed in the DSM-III-R.

Coprolalia (see below) does not have to be exclusively swear words. Many times coprolalia manifests itself as socially inappropriate or unacceptable words or phrases, such as the overwhelming urge to use a racial epithet, even though that is the last thing you want to do.
Something about the "forbiddeness" of it impels a person with coprolalia to say it, seemingly against their will.

Another important thing to remember about coprolalia is that although this symptom has been sensationalized by the media, it is actually rare, occuring in less than 30% of people who  have a severe case.
                                                                                        
Simple tics are movements or vocalizations which are completely meaningless, whereas complex tics are movements or vocalizations which make use of more than one muscle group or apear to be meaningful.

The range of tics or tic-like symptoms that can be seen in TS is very broad. The complexity of some symptoms is often perplexing to family members, friends, teachers and employers who may find it hard to believe that the actions or vocal utterances are not deliberate.