WPML Filter URL's

wpml-filter.php

<?php

function filter_language_code( $content ) {

	$new_content = '';

	$dom           = new DOMDocument();
	$dom->encoding = 'utf-8';
	libxml_use_internal_errors(true);
	$dom->loadHTML( $content );

	$anchors = $dom->getElementsByTagName( 'a' );

	foreach ( $anchors as $anchor ) {

		$href = $anchor->getAttribute( 'href' );

		/*
		if( 'XXX' ! = ICL_LANGUAGE_CODE ) {
			continue;
		}
		*/

		/* 
		$find   = 'de';
		$pos = strpos( $href, $find );

		if ($pos === false) {
			continue;
		} */

		// do what you need to do to th "href"

		$href = str_replace( site_url(), home_url(), $href ); // this might work

		$anchor->setAttribute( 'href', esc_url( $href ) ); 
	}

	$new_content = $dom->saveHTML();

	return $new_content;

}

add_filter( 'the_content', 'filter_language_code', 999 );