The Google suggestion on search form is blocked on english language. If you want to change the language you need to edit the wprentals/libs/css_js_include.php and at line 153 there is this code

if (esc_html ( get_option('wp_estate_ssl_map','') ) =='yes'){
        wp_enqueue_script('wpestate_googlemap', 'https://maps-api-ssl.google.com/maps/api/js?libraries=places&language=en&key='.esc_html(get_option('wp_estate_api_key', '') ),array('jquery'), '1.0', false);        
    }else{
        wp_enqueue_script('wpestate_googlemap', 'http://maps.googleapis.com/maps/api/js?libraries=places&language=en&key='.esc_html(get_option('wp_estate_api_key', '') ),array('jquery'), '1.0', false);        
    }

You have language=en  in 2 places

Change the en with your new language code you can find here: https://developers.google.com/maps/faq#languagesup…

VERY IMPORTANT NOTE :  If you change the langugage code after you added some listings the new search function may not work correctly. Here is why:

For ex you start by adding listings in English. A listing in english in New York will have the city as “New York”.

You switch the language to Italian and search for listings in NY. But in Italian New York is translated as “Nueva York”. So the script will compare “nueva york” vs “new york” which are 2 different things in computer languages.

The solution will be to 1. make the change right from the start or 2. relist in the new language the old listings.