Shortcode to display content based on current language.

polylang-shortcode.php

<?php
if( ! function_exists('polylang_content_func') ){
	function polylang_content_func( $atts, $content = "" ) {
		
		$atts = shortcode_atts( array(
			'lang' => '',
		), $atts );
		
		extract($atts);
		
		// Bail early if no language provided
		if( $lang == '' ) return;
		
		$pll_current_language = pll_current_language();
		
		// Bail early if current language is not same as provided language
		if( $pll_current_language != $lang ) return;
		
		return do_shortcode($content);
	}
}
add_shortcode( 'polylang_content', 'polylang_content_func' );

Conditional Shortcode Based on Language ( for another chance to find it ...)
Wow! Thank you very much, this code runs just perfect!

(for those who are not that familiar with coding, like me :-) ):
Insert the above code into your functions.php of your child-theme.
Use the short code in your wordpress pages/widget etc. like this:

[polylang_content lang=en] Language is displayed in english [/polylang_content]
[polylang_content lang=de] Sprache wird in deutsch angezeigt [/polylang_content]

Great! Many thanks again!