One of the still vaguest issues in SEO, is spelling and grammar- How does an improper form of spelling and/or grammar in pages is affecting the page’s rankings and the overall domain authority? Matt Cutts, the head of internet spam in Google, tried to answer this question in a recent video.
Matt is saying that as for the last time he checked, it’s not used yet as a direct signal out of the 200+ signals to assess quality of pages. However, Matt warns that “it would be fair to think about using it as a signal…” Meaning, it may carry some more weight in the future.
Google’s spam chief is also mentioning that they (Google search team) have noticed that there is a correlation between the ability to spell well and to the page’s Pagerank- Reputable sites (high Pagerank) tend to spell better than low Pagerank sites. If you think about it, its pretty logical- Bad spelling/grammar can cause lesser backlinks (which determines Pagerank) from other websites.
What Google does evaluate is the page reading level (third-grade level, academic level, etc). In Google Advanced Search, the users can filter the reading level (basic, intermediate or advanced) of queries by changing the Reading level filter. Using the site:YourDomain.com you can examine a whole website reading level, here’s an example of Wikipedia’s reading level:
Back to spelling and grammar, Matt is saying that even if Google would had the best language identification algorithm, there will always be some pages that would be evaluated wrongfully as a different language, which will obviously cause them to look like they awfully written. It is even getting more complicated when several languages are involved in the same page. Because of these reasons, it is pretty problematic to make it a direct signal.
Conclusion
Although spelling and grammar aren’t compute as direct search signals (factors) yet, they still have affect on the site’s rankings- Fewer websites would link to the page and it would distance many readers. In the future it may change, as Google develop their algorithm.
Here’s the full video of Matt Cutts interpretation on spelling and grammar: