Backlinks and Site Language

Just a quick Question. I tried to search for the Answer, but couldn't find it.

I have a few german Sites. I was wondering if I should put my Backlinks on german Sites only, or if it doesn't matter what language the Site with the Backlink has.

I always try to post backlinks on a site of the same language to increase the chances of my link getting traffic. I have never ever been penalised by leaving a link on a site using a different language though and if the links are relevant to your niche, i would definitely try to gain a backlink from them.

ok, thanks