There is no official policy regarding "good English" or "bad English" in this group. A good number of participants (... [looking in the mirror] ... and even maintainers...) are not native speakers and prone to make grammatical or stylistic mistakes. While such things as netspeak, slang, or foul language generally should not be used in this community except when discussing those subjects, before ferociously chastising a poster please think twice: in all likeness, he or she is a foreigner and does not have full understanding of the sociocultural baggage attached to a particular language style.
On the other hand, a friendly comment politely pointing out a mistake, whether grammatical or stylistic, is always in place.
At the same time, I allow myself to extend the following advice to non-native speakers, like myself. Please try to use *standard* English in your post. Things that you may think are "cool" and demonstrate your command of colloquial English may come through as childish or rude, or woefully uneducated. For Russian speakers, a good analogy would be using the verb ложить in a linguistic forum!
To summarize, we encourage the posters to use, when they can, standard, educated English of any variety, and if there are compelling reasons to post in another language, to precede the post with a brief introduction explaining what the post is about.