Multi language website is important when your target audience located in different countries that speak different languages. For example if you have English website for English audience and also want to target French speakers then your need to create a different websites for different audience.
Here are tips about multilingual websites:
Keep it easy and understandable, this help user to identify which language website they are reading. You can create a sub domain or create sub page to identify language. For example
If you want to target French speakers then use following URL structure
This helps users and search engines to know for which country this website translated for. If you want to make URL in non-English then use UTF-8 character encoding. Always use UTF-8 encoding if you are not sure which one is perfect for your website.
Tips for properly crawling and indexing multi language website
Google recommend not use automated translation tool for language translate. Most of the automated language translation software not work perfectly and if your website represent wrong information or if your user unable to understand what you have written then you might loss your business.
Cross link all your language pages, if someone viewing your product page in English put a direct link to other countries so search engines and user can easily find same detail in other languages. This make easy for users to navigate to your website.
Also Google not recommend automatic redirects as this prevent users to view your website in other language. If you have done automatic redirects, if English reader viewing your site from France then they probably unable to view English version of your site and you loss your potential visitors. Write different content for different language, don’t set cookies to redirect user to other language.
If you have any further question please post comment here and I will be happy to answer your questions.