TYPO3 - Language menu is not showing on mobile version

I don’t have much experience with TYPO3 and I find it hard to find some things. The language menu is not displayed in the mobile version and I cannot find a solution.
In the browser inspector I notice that the div is disabled and the content is empty any suggestions?

<div class="topbar-mobile__button"></div>

I have reviewed the page and template options but I have not found options nor in the typo3 documentation.
CMS version is 11.5

TYPO3 core is not responsible for the page layout of your front end as the front end rendering has to be defined by a non-core extension.

In that extension you (or the extension author) needs to define templates for the page layout.

Nowadays it probably are FLUID templates splitted in Layouts, Templates and Partials. They include the HTML-Markup and use variables and some control structures to build the resulting page from the data.

I assume you used an public available extension/package like Boots-Trap-Package you need to analyze the FLUID-templates of that extension (which also may include Javascript and CSS) to identify what is displayed under which condition.
Then you can modify (do an override in your own extension instead of modifying the extension from a public repository! otherwise you would not be able to update it.) the given templates by copying the original files and configure your instance to prefer your versions instead of the original.