In those detailed tutorials, we’ll follow a few steps to create a multilingual Joomla site.

• If you have Joomla 4 read: https://www.joomshaper.com/blog/how-to-create-a-multilingual-site-in-joomla-4-using-helix-ultimate
• If you have Joomla 3.10 read: https://www.joomshaper.com/blog/how-to-create-a-multilingual-joomla-site-using-helix-ultimate

Good to know:

• Translating your Joomla site into different languages gives you a chance to start ranking in Google for queries in new languages.
• A multilingual website serves the same content in multiple languages. But webmaster or site owner has full control over what subpages would be translated. 
• Most of the top Joomla extensions are translation-ready. However, they may not be translated into all languages (your can be missing) or some phrases from them are hard-coded.

The most important tips:

• Before you will start, install the needed languages in Joomla and prepare professional translations.
• All articles, k2 items, modules, and Pages (SPPB) can be assigned to different, selected languages.
• If you have a Multilingual Site, an off-canvas (mobile) menu also should be prepared for each language.
• About Mobile Menu - remember to assign Menu modules in "offcanvas" position for each language.
• Don't use fonts that aren’t international, It’s an easy one to forget, but make sure you choose a font that displays special characters. French accents (like this: é) can totally change the meaning and pronunciation of a word, so they’re important to include and get right!
• It would be a good idea to first test your skills on a test site and verify that everything works correctly before you will start making changes on the production website.
• And once you’ve translated your site, you can add and display a language switcher module.