The service links on your front page point to the spanish version of your site. For example Market Research has the link https://datrick.com/investigacion-de-mercado/. If you want it to direct to the english version, change the link accordingly (i.e. https://datrick.com/en/market-research/).
I think its because of your low network bandwidth and if you wait in general tab or connect to better network, it will appear there. The reason is this part (new languages) needs to be downloaded from network.
WordPress functions are PHP. you should start here: https://developer.wordpress.org/ As the first steps I recommend to study: Theme development: https://codex.wordpress.org/Theme_Development The Loop: https://codex.wordpress.org/The_Loop And The WP theme hierarchy: https://developer.wordpress.org/themes/basics/template-hierarchy/
http://wordpress.org/extend/plugins/wcm-user-language-switcher I tried wcm language switcher, it only supports for users, not for guest who are not logged in. anyway thanks to kaiser & brasofilo. Finally, I got a solution with theme switcher plugin http://wordpress.org/extend/plugins/theme-switcher I duplicate my theme and keep one is default, then create next one for new-language. even it takes more space … Read more
Why my wordpress admin panel shows only English Language in setting?
Yes. Language Switcher WordPress Plugin qTranslate WPML – the best, but commercial
I’m totally shocked. After hours of trying things and testing, I finally found the “Settings” then “Readings” option below: “Encoding for pages and feeds”. After changing from UTF-7 to UTF-8, everything looks good again. And even stranger, after changing it to UTF-8, the option disappears from the page. According to WordPress site, this option was … Read more
If it is a new install, the best option is to install WordPress in Russian. You will have English also available from “Settings > general > Site Language”. You can also manually install additional languages: download the files from this respository and upload theme to “wp-content/languages” directory. The new installed languages will be available in … Read more
Localize WordPress or write and load special localization for your language specialy for thickbox. Thickbox dialogs support localization provided by WP Update – Let’s Check 1. You have uncomented string <code>define(‘WPLANG’, ‘pl_PL’);</code> in your wp-config.php 2. You have localization files in wp-content/languages/
I don’t remember doing it in practice, but from quick look at documentation there is a load_child_theme_textdomain() function for precisely that. Once you use it with your copy of translation (note that timing and such, as per documentation) your changes should override parent theme’s version.