get_cat_ID returns 0 if used with Polylang

Hi everyone. I’ve just started to use WordPress and am working on my own theme. Since my page has to support multiple languages I’ve decided to use the Polylang plugin. Additionally I’ve added a category and its translation in the backend. Let’s call the category names “Services” (for English) and “Dienstleistungen” (for German) So far, so good.

Now I want to write a function do_something($catname) that generates some HTML code based on the given category and current language. Thus it’s called like do_something("services") in the theme (thus hardcoded parameter) and should use the correct translated category in its logic.

For that purpose I’ve wanted to use get_cat_ID($catname) or get_term_by('name', $catname, 'category') to get the actual ID and get the translated category ID by calling pll_get_term($cat_term_ID). If the page language is English everything works fine, both get_cat_ID and get_term_by return the correct ID for the parameter “services”. As soon as I switch to German (with Polylang’s Language switcher), both return 0 resp. null. Thus I have no chance to call pll_get_term if the language is switched to something different than English. Maybe I am missing something or have a wrong understanding of these functions. For me it isn’t clear why something like get_cat_ID("services") doesn’t work if the page is set to another language.