Gettext filter example

gistfile1.txt

function my_text_strings( $translated_text, $text, $domain ) {
	switch ( $translated_text ) {
		case 'students' :
			$translated_text = __( 'clients', 'woocommerce' );
			break;
		case 'courses' :
			$translated_text = __( 'programs', 'woocommerce' );
			break;
		case 'teachers' :
			$translated_text = __( 'counsellors', 'woocommerce' );
			break;
	}
	return $translated_text;
}
add_filter( 'gettext', 'my_text_strings', 20, 3 );