mi idioma original es español

my original language is spanish
language
When I downloaded the IceCat browser,
 I really liked it, but when downloading and executing the packages
(which are) [] icecat-60.7.0.es-MX.langpack.xpi
or any other does not change the language even
if I reopen the browser.
So what can I do to be able to install the language packs that
I need to understand the browser.