Handbook drupal 9? does it exist ? where can I order such book? 

I've seen many people with this problem in several forums an threads, but can't find information on how to solve this.

The problem is that some fields in menu links are not translatable (others like title or description are):

Trying to translate menu links

I can't see the way to add link as translatable in regional -> content-language:

Custom menu link translation options in regional content-language.

Randomly, translated content is showing a 404 page.
Also, unable to access translated content in Admin content listing view, it's redirecting to default the English language on clicking edit.

The wrong URL is being generated in the edit for e.g

1. Italian(langcode - "it") =>  /in/ode/[nid]/edit
2. Nepali(langcode - "ne") =>  /in/ode/[nid]/edit

I have faced the above issue for Italian and Nepali language so far, unable to understand what's wrong with these two languages.

Hello,

I installed Drupal 9.0.2 using the recommended Composer template, setting the default Language to German. Nevertheless I tend to find the English labels more to the point at lot of times. However, when trying to download the respective translation files (for more than 50 projects!), they are not found. I wonder what I am missing...

Thanks for any hints
H. Stoellinger

Good evening / morning everyone,

I was about to finish the new version of my website with Drupal 8.8.5 and a theme built mostly with paragraphs and flexible content. I understand that (and why) some fields in paragraphs are not translatable with the usual process. No problem with that, as I have the issue only one two pages which are not intended to be modified (home page with a slideshow and photo galleries list page).

Hi,

I've installed Drupal in english, and added french language later.

According to the settings in admin/config/regional/language, French is now the default language of the website.

The admin menu is translated in french, which is nice, but the labels of the main navigation menus are translated too, which is a problem.

For example, if the label is "Switch" (as in "Nintendo Switch"), in the menu it appears as "Changer" (a french translation for "to switch).