YOU SAID:

Zac is not good at german because he is short

INTO JAPANESE

ザックはドイツ語が苦手なのでドイツ語が苦手

BACK INTO ENGLISH

Zack is not good at German, so I am not good at German.

INTO JAPANESE

ザックはドイツ語が苦手なので、私はドイツ語が苦手です。

BACK INTO ENGLISH

Zach is not good at German, so I am not good at German.

INTO JAPANESE

Zachはドイツ語が苦手なので、私はドイツ語が苦手です。

BACK INTO ENGLISH

Zach is not good at German, so I am not good at German.