repot

resolved here http://wordpress.org/support/topic/polylang-and-recent-post-widget-how-to-force-english?replies=4#post-5044381

Code to be modified:

echo ( $title )? $before_widget . $before_title . $title . $after_title:$before_widget;

		$num_posts_query = new WP_Query( (( $category ) ? "cat=".$category."&": '')."showposts=".$posts_num."&offset=".$offset );

		if( $num_posts_query->have_posts()) {
		$counter = 0;
		?>
		    <div class="wpalp">
			<ul class="wpalp_thumbnails<?php echo ($thumbnails_only)?' wpalp_thumbonly':''; echo ($thumbnails)?' wpalp_thumbs':'';?>">
<?php			    while( $num_posts_query->have_posts()) : $num_posts_query->the_post();
			    update_post_caches($posts);
				$counter++;
				?>

Waiting for a right kind of pilot to come… Please, really need it.