The meaning of HL parameter and GL parameter in HTTP request

Reference: Https://developers.google.com/custom-search/docs/xml_results?hl=en&csw=1

1.GL: Country Code

Gl
Description	Optional. The GL parameter value is a two-letter country code. For websearch results, the GL parameter boosts search results whose country of origin matches the parameter value. The Country Codes section for a list of valid values. Specifying a GL parameter value in Websearch requests should improve the relevance of results. This is particularly true for international customers and, even more specifically, for customers in english-speaking count Ries other than the United States.
examples	This is the request boosts documents written in the United kingdom in Websearch results: Q=pizza&gl=uk

2.hl:host language

hl
Description	Optional. The HL parameter specifies the interface language (host language) of your user interface. To improve the performance and the quality of your search results, your are strongly encouraged to set this parameter expli citly. Interface Languages section of internationalizing Queries and Results presentation for more information and Suppor Ted Interface Languages for a list of supported Languages.
examples	This request targets ads for wine in French. (The Vin is the French term for wine.) q=vin&ip=10.10.10.10&ad=w5&hl=fr

So, these two parameters can be used to locate the region.