diyAudio uses a software platform based on English. So all posts and post titles must use English for the software to operate OK, otherwise search results and thread title listings won't work properly.
Current policy is that providing an additional language to go with the English in a post is ok. It means people will post exactly what they want to say and not have anything lost in translation. Other members speaking that language may be able to then better assist the member and contribute to the thread if they got their translation to English a bit wrong.
So, please use English first, then add an additional language for better understanding and if help is needed.
I suggest that for now, let's see how it goes with this policy. I will document the policy in the new year and post into the rules