Truncate the title of Yoast's WordPress SEO breadcrumbs.

truncate-yoast-breadcrumb.php

<?php
/**
* Truncate the title of Yoast's WordPress SEO breadcrumbs.
*
* Sometimes you will have post titles which are longer than you want
* them to be in your breadcrumbs. This will allow you to set a maximum
* length for the post title used in Yoast's breadcrumb function.
*
* @author FAT Media, LLC
* @link http://wpbacon.com/tutorials/truncate-wordpress-seo-breadcrumbs/
*/
add_filter('wp_seo_get_bc_title', 'wpbacon_truncate_bc_title');
function wpbacon_truncate_bc_title() {
	// Get the title of the current post.
	$title = get_the_title();

	// Determine the length of the title.
	$title_length = strlen( $title );

	// Set a limit for the breadcrumb title.
	$limit = 55;

	// Truncate the title.
	$truncated = substr( $title, 0, $limit );

	// Add an ellipsis if the title has been truncated.
	if ( $title_length > $limit ) {
		$truncated .= '...';
	}

	$link['text'] = $truncated;

	return $link['text'];
}

@vj009007 - Just use the core WordPress wp_trim_words() function which takes care of all that for you ;)

https://developer.wordpress.org/reference/functions/wp_trim_words/