Simple way to get two language WP site

You can use below code for translating strings:

add_filter('gettext', 'translate_text');
add_filter('ngettext', 'translate_text');

function translate_text($translated) { 
    $translated = str_ireplace('Choose an option', 'Select', $translated); 
    $translated = str_ireplace('Original Text', 'Your Replacment Text', $translated); 
return $translated; 
}

But I have no idea for translating complex contents. I know you don’t want to use plugins but as my research, we must write php code very heavy as a plugin to work. I recommend WPGLOBUS, It create an icon for every post or page field like title, content or categoris and more, while you click on the icon you can enter your translation for unlimited number of languagess which you set before in the settings, plugin generates an yoursite.com/ru address without generate or need to any new stylesheet, js or pages or load any additional file.