A META Tag is the hidden text placed in the HEAD section of your HTML page. META Tags are used by most major search engines to index websites based on their keywords and descriptions. It is very important to use META Tags as well as a good TITLE if you expect to be found in most search engines. However, META Tags are not the only thing search engines will look at when ranking sites. Some search engines will ignore META Tags completely. Most search engines will also index your body text. Please fill out all the information and click "Generate Meta Tags". Your META Tags will be displayed and you can then cut and paste them to your HTML source code.
When titles and meta tags are properly optimized, search engines have the necessary information needed to optimally display and rank your web page in their search results. If not optimized for search, your rankings and click-through traffic will suffer. Visit the SEO Learning Center to learn how it's done the right way.
Most of the tradiational meta tag generator give you the option of including language meta tag. Now it is not recommended by W3C standards itself, for more information Read here.