in reply to Non-English posts on Perlmonks

Posting in non-english is not good for the following reasons:
Let's assume that someone posting here in a non-English language doesn't have the knowledge to post an understandable article written in English. Their alternative is to not post.
  • You will miss usefull comments of people that dont speak your language.
True, but you still might get comments of people understanding your language, which is better than not getting any comments, which happens if you don't post at all.
  • You will divide the power of the perlmonks community into 'islands' of knowledge
Yeah, and? It's not going to reduce the size of the "main", English-speaking island. But it might cause additional islands to form, increasing the total land-mass. And if their are people who understand both English and some non-English language, they can act as bridgebuilders, linking the various islands.

I don't get what you are saying with your first two points (maybe that's because I'm not a native English speaker).