Filter fixing WPML appending language codes on term slugs

wpml-term-slug-fiter.php

<?php
/**
 * Filter fixing term slug for WPML plugin
 * always (!) removes -{language code} (including repetitions like "-de-de-de") from the end of the slug before it is saved in the database and after WPML modified the slug.
 * Note that this will always happen, even if you typed in the language code yourself in the input.
 * The function will not strip combinations of different language codes like "-de-en-de" (this would certainly result in "-de-en").
 *
 * @author    Jannik Portz (@janizde)
 * @param     string      $slug       The slug coming from WPML_Term_Translations::pre_term_slug_filter
 * @return    string                  The slug without language codes at the end
 */
function wpml_fix_filter_term_slug ( $slug ) {

	/** You may have to change this, depending on what languages you are using */
	$language_codes = array( 'de', 'en', 'ru', 'sp', 'it' );

	foreach ( $language_codes as $l ) :
		$pattern  = '/^([a-z0-9-]*?)(-'. $l .')+$/';
		$count = 0;
		$slug = preg_replace( $pattern, '$1', $slug, -1, $count );

		if ( $count != 0 )
			break;
	endforeach;

	return $slug;

}

add_filter( 'pre_term_slug', 'wpml_fix_filter_term_slug', 11, 1 );