Hi nitish7,
I can see how this can be confusing. Let me explain.
Changing the “Default Language” in the plugin does not change the initial language of your website. The “Default Language” setting is there for Google to understand how to configure translation on your site after a language is clicked in the Google Language Translator.
So Google Language Translator changes your website language once a user clicks on a language; it does not change the initial language of your website.
If you want your website to load immediately in Spanish language, you can add a language file into your WordPress installation that will change your entire website language into Spanish. You simply download the Spanish language file and then install it into a special WordPress folder.
Here is how you can do that, step by step: https://codex.www.ads-software.com/WordPress_in_Your_Language. (You could probably also just use another plugin to accomplish this, but in my opinion, less plugins is better.)
Then once you do this, your website will be fully displayed in Spanish, and then users can use Google Language Translator to translate your webpages from that point forward.
Hopefully that makes sense. Let me know if you have any questions!
For now, I’m going to close this as resolved but please continue to post here if you have other comments as to this topic. I will help out anyway that I can.
Thanks, Rob