Gets the locale of the site visitor's browser.
A locale, also known as an IETF language tag, is an abbreviated code that defines the language, country, and other aspects of the site visitor's browser, such as number format and date format.
Some common locales include:
"en-US": English, United States"en-GB": English, British"es-ES": Spanish, Spain"de-DE": German, Germany"ja-JP": Japanese, Japan"fr-CH": French, Switzerland"it-IT": Italian, Italy