function translate_yandex_text($source_text, $lang='ru-en', & $translated_text, & $error_description)
{
     $translated_text = "";
     $error_description= "";

     // there must be a character between the words %20
     $source_text = str_replace(" ", "%20", $source_text);
    
     // your key should be here yandex api
     $yt_api_key = "trnsl.1.1.20181108T121523Z.669d96c33aec2412.c32c6acb77efd.....49f91d4904088ad722a89";

     $url = 'https://translate.yandex.net/api/v1.5/tr.json/translate?' .
          'key=' . $yt_api_key . '&' .
          'text=' . $source_text. '&' .
          'lang=' . $lang . '&' .
          'format=plain&' .
          'options=1&p=2';

     $curlObject = curl_init();

     curl_setopt($curlObject, CURLOPT_URL, $url);

     curl_setopt($curlObject, CURLOPT_SSL_VERIFYPEER, false);
     curl_setopt($curlObject, CURLOPT_SSL_VERIFYHOST, false);
     curl_setopt($curlObject, CURLOPT_RETURNTRANSFER, true);

     $responseData = curl_exec($curlObject);

     curl_close($curlObject);

     $result_arr = json_decode($responseData, true); // convert to an array
     $translated_text = $result_arr['text'][0];
     $error_description= $result_arr['message'];

     if ($error_description=="")
          return true; // no errors
     return false;
}

// translate the text from English into French en-fr
$source_text = "Hello my friend";
if (translate_yandex_text($source_text, 'en-fr', & $translated_text, & $error))
     echo $translated_text; // on the screen we will see Bonjour, mon ami
else
     echo $error;