nav_logo filter

functions.php

<?php
// we are going to filter navbar_logo section option on the fly..
add_filter( 'pl_opt-navbar_logo', 'change_logo_on_lang' );
function change_logo_on_lang( $val ) { // $val is the value of the setting.

	// use some polylang data to get current language
	global $curlang;
	$curlang = $this->curlang->slug;

	// asumming the slug is nl or en

	if( 'en' == $curlang )
		return 'http://some-image-for-nl.png';
	else
		return 'http://some-image-for-en.png';
}