I've run into this usage several times, in the comments of sites like YouTube, usually as a joke in response to having one's grammar or spelling corrected. To paraphrase:
I'll try to English better :)
Presumably implying that their English needs improvement through example, even if the original mistake had been a typo.
My question is, is there a serious context where using 'English' as a verb would be grammatically correct? Or maybe it's on its way to becoming a new word due to frequent incorrect usage?