Google has launched a new advanced search tool that filters results by reading level. Based on how Google evaluates the website, it will annotate the results for three reading levels: basic, intermediate, and advanced.
To try it out, click on the "Advanced search" and type in your query. The option is located under "Need more tools?" and lets you select only your desired reading level, or results annotated with the reading level. Type in your query, then hit advanced search and you'll see something like this:
When you're done with the reading level filter, click the X in the right corner of the Reading Level blue bar to return to regular results.
(via Search Engine Roundtable)