Ensure that Polylang plugin is loaded on Ajax request, to ensure calendar output is translated

gce-load-polylang-on-ajax.php

<?php
/*
Plugin name: GCE Load Polylang on Ajax requests
*/

function gce_load_polylang_on_ajax() {
	?>
<script type="text/javascript">
if (typeof jQuery != 'undefined') {
	jQuery.ajaxSetup({
		data: { pll_load_front: true }
	});
}
</script>
	<?php
}

add_action( 'wp_head', 'gce_load_polylang_on_ajax' );