Spell issues in vim

From vim 7.0,  a native spellchecker is integrated which outperforms vimspell script. Gernerally, you do not need to do any works to set the spell issues as before. What the only thing you need to do now is to set the languages you want to check during your typing.

the command is:

:setlocal spell spelllang=en_us

for german

:setlocal spell spelllang=de


or simply:

:set spelllang=en_us
:set spelllang=de


 
I do not figure out what is the difference between these two commands.

If you have not the spell files for German, vim will prompt you to download the related files. Just do it.