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The HTML lang attribute is used to identify the language of text content on the internet. This information helps search engines return language-specific results and it is also used by screen readers that switch language profiles in order to provide the correct accent and pronunciation.

Here's the explanation on How to set the HTML lang attribute in Next.js?

Check out the article on my blog - https://codewithsnowbit.hashnode.dev/how-to-set-the-html-lang-attribute-in-nextjs