I'm not sure if this is exactly what you want but read the page from the macOS User Guide Write in another language on Mac
The summary says:
Write in another language on your Mac with additional keyboard layouts, known as input sources. To use additional input sources, set up your Mac to write in another language, then switch to that language when you want to use it.
You can quickly switch languages using your keyboard or the Input menu, or remain in your primary language and use the accent menu to enter characters with accent marks when writing.
Also in
Change the language your Mac uses Apple says
Although your Mac is set to display the language of the country or region in which it was purchased, you can choose a different language to use. For example, if you bought your Mac in the United States but you work primarily in French, you can set your Mac to use French.
You can also choose different languages for individual apps. For example, if your system language is set to Simplified Chinese, but you prefer to use a certain app in English, you can do so.