Limburg is the most southern province of the Netherlands.
Most people (roughly 78%) in Limburg speak Limburgish in every day life, a regional language closely related to Dutch and German. Dutch is the official language used for practically all forms of official (and most unofficial) written communication. In the larger cities, Dutch is also the main colloquial language. The majority of the people futhermore speak English and German in various levels.
The Dutch railway serves Limburg with regional branches and intercity-branches to Amsterdam and The Hague. German railway links connect Heerlen to Aachen and Venlo to Mönchengladbach by local trains. Maastricht is connected to Liege in Belgium by local train. On weekdays there is also an intercity train leaving towards Brussels from Maastricht, on weekends, transfer in Liege, but this line will be canceled from December 2011.
To and from Nijmegen there are two options. First one is with national railway company, NS, taking the train from Maastricht to Den Bosch, and then taking from there another train to Nijmegen. The other one is jumping in the direct train, run by Veolia; even though it goes directly between the two cities, this train is way slower than normal IC trains and also more expensive than traveling with NS.
The picturesque southern part of the province, Maastricht-Hill Country , is very popular with bikers. Be warned that the terrain is very hilly by Dutch standards.
Limburg is famous in the Netherlands for its local beers. Most limburgian people have specific beers that they drink in their region. The known local brands of beer in limburg are:
The minimum age for drinking alcohol is 16 years old. The Dutch government is working on raising the drinking limit to 18 years old.
Although travelers will encounter few problems, Limburg is quite densely populated and crime is relatively common. Drug-related crimes are more widespread than in some other Dutch areas, due to Limburg's location on the German and Belgian border and the associated smuggling potential. If you do not seek contact with drug traffickers however, you are unlikely to notice much of all this.
For the rest, common sense will generally be enough to keep you safe. Prostitution is legalized in all of the Netherlands but make sure to use condoms as STD's remain a problem. Pick pocketing isn't nearly as much of a problem as it is in e.g. Amsterdam, but keep an eye on your personal items nonetheless. As in other Dutch regions, you might meet an occasional drug addict or wanderer on the streets, asking for a bug. The social welfare system is pretty well arranged and begging (which is illegal) is often related to drug addiction. Kindly declining is usually enough to send them off. An exception are homeless people selling "street newspapers" ("straatkrant"), often at supermarket entrances. This is a legal and organized initiative in the Netherlands which you may support, but sellers should visibly be wearing an ID card.