Where do I specify the language of my website?

According to W3C, you can add lang=”en” (for english) attribute to your HTML tag and this is still valid for HTML5.

Here are some other options for the lang attribute:

“en”: English

“en-US”: the U.S. version of English.

“en-cockney”: the Cockney version of English.

“i-navajo”: the Navajo language spoken by some Native Americans.