Multi-language and translations
On Configuration > Regional and language you have an overview over all language-settings you can perform on Drupal. You can create/delete languages for your website. Set redirects on browser depending languages and much more. Drupal gives you a lot of options.
You can translate every page/block/panel on the page. Just simply press the "translate" button and select the target language.
If you can not find a certain word which you want to translate, please try the Configuration > Regional and language > User interface translation. Strings which are re-used a lot are stored in here, so you only have to translate them once. The search in here is case-sensitive. Be careful with lowercase and uppercase letters.
If you dont want to use translations at all, you can simply delete all ohter languages except the root language and remove the language-switcher form the footer.