Language study or student applicant visa?

I was told that you must apply for a “student applicant visa” if you want to enroll into a university after the language study. However I intend to study German for a year (because that is how long it takes to get from A1 level to B2) then take the DSH or TestDaf test for university enrollment. Is there any realities about the “student applicant visa” that I need to know about, like how long do I have to enroll into a university, or is it just a visa that allows me to change the residence permit from language study to university study?

I just want to make sure I get the right visa from the start.

Why would you spend one year on a tough language course ? I assume most universities in Germany teach in English.

Why would you spend one year on a tough language course ? I assume most universities in Germany teach in English.[/quote]

No, the prevailing language there is still German. Also they don’t really have too many English programs in Geology or related fields. Most English programs I can find are in Engineering.