To learn any language we have to study about that language,syntax of language and practice regularly..

German language is categorised as type 2 language.The fsi estimated that it generally takes 30 weeks or 750 hours to learn..but it is not enough to master it because it requires lot of practice,if you will use it on daily basis you can learn it fast in compare of others.for more updates you can visits:

it also depends  on the efforts you are wiiling to put in,how often you practice ,which source and from which techniques you wii learn.

the main important thing is how much time you are giving to learn german.

hope it will helpful!!!!!

thanks!!!!