gettext.php

<?php
// Remove the opening PHP tag above if your file already includes it

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; 
}