If you wish to change language, a multilanguage plugin would be the best and easy solution.
Here are the options I know of
1. FREE If you want a plugin that uses an API to translate (like Google API, or Bing API) – and you don’t have to make any modifications to the translation, you can use something like Transposh – https://wordpress.org/plugins/transposh-translation-filter-for-wordpress/
3. PAID If you want to spend the time and manually translate each item on your website to multiple languages, you can use WPML – http://wpml.org/ This is the most time consuming option of all.