To change a particular string, you can use the gettext
hook:
/*
* Using priority 20 to override the default 10.
* If another theme or plugin has a higher number,
* you might need to raise this.
*/
add_filter( 'gettext', 'wpse_change_strings', 20 );
function wpse_change_strings( $translated_text ) {
// If this is the specific string to change, update it.
if ( 'Register' === $translated_text ) {
// Change this to your desired string.
$translated_text="Updated Call to Action";
}
// Always return the text, whether we changed it or not.
return $translated_text;
}
The above is case-sensitive. You could use strtolower($translated_text)
to compare if you’d like to change the text regardless of capitalization.