Use caution at night at the central station. Avoid talking to the groups there. Use your normal precaution generally and you will be safe. You can talk to every police officer in the city. Normally the are wearing green-brown clothes, but maybe you will encounter one in black-blue.
contact
In the city's main shopping street, Lange Strasse, you can find some cafe's with wireless. Also internet cafes are available.
talk
English is not spoken all over the place, German is obviously the first language. The bigger hotels and young people mostly speak English. Also you can communicate in Turkish as Delmenhorst has a descent number of immigrants.