Learn how to implement multi-language in Lightning Web Components (LWC) using custom labels and how to use them in Apex class for seamless localization
Custom labels should be imported in the js file using the Import statement. Then it can be assigned to a variable and used in HTML. Follow the best practice of Adding All labels to an Array and use values from an array to avoid confusion.
WelcomeComponent.js

WelcomeComponent.html

When user language is English

When user language is changed to German

Custom labels are easily usable in Apex classes With the following syntax
System.label.API_Name_of_label

The above code will return the translation value of the label for the current user language. If the translation is not added for the current user language, it will return the default value in the label.