What decides in which language the CAP application will open?

[Abap_Explained]

Hi Guys,
For my trial account. I have created a sample project with a sample app. When I open the app it adds the sap-language:

[odata] - GET /odata/v4/bookstore/$metadata { 'sap-language': 'PL' }

 I would like to set it to EN as default. How can I overcome that?
The trial Account language is set to English, and my SAP account is also set to english.

I know I can add, to the request.:

?sap-language=EN

But I was wondering where the default setting is. Or does it take it from the Geolocalication, IP... whatever? 

[JoffyJohn · Accepted solution]

The CAP app's default language is usually determined by the browser's language settings or request headers.

[Abap_Explained]

Thanks. Changing the browser language helped.

[Tahemmout]

Hello @Abap_Explained,

As @JoffyJohn mentioned the CAP service will follow your browser locale, but you can set a default language in the package.json as mentioned in the capire docs: Set default language 

[Abap_Explained]

For i18n yes, but not for default buttons like:

But yes. I guess it makes sense that it's taken from the browser language.