You can check or train your German Grammar (structured according to the European Framework of Reference for Languages). Please use this website (Website of "Deutsch Akademie").
It is an advantage for foreign applicants for a place of study if they are able to attend a language course before leaving their home country. Sometimes these are offered by the home university or the German cultural institutions (e.g. the Goethe-Instititut) in the home country. The addresses of such institutions can be obtained from German embassies and consulates.
You will find the addresses of language schools in the so-called yellow pages (Gelbe Seiten) of the Telekom phone book. In Germany there are branches of the Goethe-Institut at which intensive language courses take place in various towns. Further information on these can be obtained from:
Information on university vacation courses and holiday courses is available from:
Deutscher Akademischer Austauschdienst (DAAD)
In Bielefeld and the surrounding region there are plenty of language courses on offer.