What is a shortened URL? Basically, some of Odoo controllers are addressed by unique identificator of the related object. So, if blog ID is 1, it might be accessed by ...post/1. The last part ‘/1’ might be enriched with any key words, while the target would be still the same:

* post/1 = post/my-post-1 = /post/my-great-post-1 = /post/[any-transliteration]-1

As soon as a user reaches the address, the URL is adapted to a default one: post/[BLOG POST NAME]-1.

BLOG POST NAME is language specific. So, if you translated that, it would be included into the URL on the target language. Let assume the blog post name is ‘Good’ and its translation to French is ‘bon’. Then:

* Default URL = post/good-1

* Default URL in French = fr/…./post/bon-1

Take into account those features relate ONLY TO controller-based pages, where those features are configured: blog posts, e-shop products, forum questions (look at the above URL on this page).

It does NOT work for website pages you created manually (through new > page mainly). The latter do not have IDs inside, so their text address is considered as unique locator. Technically, they do not have an own controller starting from the version 11. So, custom page title does not influence its URL, and it is the same for all languages. For that case have a look at the app I referenced in the answer below.