...just as you’re judging others’ writing, so the engines judge yours... - Bing
The Bing Webmaster Blog confirms many SEO practitioners assumptions that Bing’s search ranking algorithms do in fact consider poor grammar, typos and poor language to be part of their search ranking factors. Google is less clear on the issue, but certainly those same factors play a role in their scoring system.
Things like sentence structure (run-on sentences, lack of punctuation, over punctuation, etc.) can hurt website rankings. Establishing an editorial process will help with SEO.
This might all seem a bit “down in the weeds”, but just as you’re judging others’ writing, so the engines judge yours. If you struggle to get past typos, why would an engine show a page of content with errors higher in the rankings when other pages of error free content exist to serve the searcher? Like it or not, we’re judged by the quality of the results we show. So we are constantly watching the quality of the content we see.
SOURCE: Duane Forrester, Bing,