How to localize React app that uses third party UI libraries like MS Fluent UI and Material UI? 

When it comes to localizing a React app that uses third-party UI libraries like MS Fluent UI and Material UI, it's important to remember that localization and UI component libraries are two separate things. Localization involves translating the text and adapting the interface to different languages and cultures, while UI component libraries provide pre-built components for designing the user interface.

To localize your React app, you'll need to use a localization library that is compatible with React. There are several popular localization libraries available, such as react-intl and react-i18next. These libraries provide tools and utilities for translating strings, formatting dates and numbers, and adapting the interface to different languages.

Once you've chosen a localization library, you can integrate it into your React app and start translating your content. It's important to keep in mind that localization should not be tightly coupled with the UI component libraries you're using. This means that you should avoid hard-coding strings and other localized content directly into your UI components, as this will make it difficult to change the content without modifying the component code.

Instead, you should use the localization library to manage your localized content separately from your UI components. This will allow you to easily update and change your localized content without affecting the underlying UI components. By keeping localization separate from UI components, you can ensure that your app is flexible and easy to maintain, even as you update and change your UI components over time.