Language selector Drupal 8 I can't seem to get a Language Selector to appear on my page.html.twig (or in a block). I must be doing something wrong, I can perfectly translate my content by I can't switch language (unless I change the URL myself).
This guide shows how to create a multi-lingual content.

https://www.ostraining.com/blog/drupal/d8-multi-lingual/

If not success please post some code you're trying to do. Remember to clear the cache.