When you already install and set up the Langify Shopify app, please go to the Product Labels & Badges Pro app and create a new label.
To assign the label to the store-language, please enter the name as following [language-code]+label name.
Take note that the English language might not have the code but you must still have it in the name, for example:
Then, the label is shown accordingly to the language.
Hope it is helpful.