Language group and Language in URL
If you have multilingual website, URL needs to have language in it. There are two types of multilingual websites:
1. Website is multilingual for all regions. It means you have more than one language. For example, English, French and Danish.
2. Website is multi region, each region has its own language(s). It means you have more than one region (Language Group) and each region can have one or more languages. For example, region one has English and region two has French and English.
If you have a website with more than one language group, go to the Settings/Language. in settings tab, make sure Language Group in Link is On.
If you have only one language group, URL doesn't need to have the language group inside it. Core automatically refer the language inside URL to the one and only language group.
Default Language
To select the default language of your website, go to the Settings/Language. In settings tab you can select default language.
On Default Language: Link, If you select Without Language, default language links will not have the language inside their link. For example http://example.com/post/my-post-title. If you select With Language, default language links will have the language inside their link. For example http://example.com/en/post/my-post-title.
In both method, visitors have access to the URL with language in it.