Working with WordPress I often stumbled upon a misunderstanding of clients, what is a point POST or Media in admin panel. I recently found a simple and effective solution to this problem on the Internet.. WordPress has a standard solution to replace some of the default admin headers with the function str_ireplace(). I won't tell for a long time., just sharing a working example.

add_filter(  'gettext',  'wps_translate_words_array'  );
add_filter(  'ngettext',  'wps_translate_words_array'  );
function wps_translate_words_array( $translated ) {
     $words = array(
			// 'word to translate' = > 'translation'
			'Posts' => 'Article',
			'Post' => 'Articles',
			'Pages' => 'Stuffing',
			'Media' => 'Upload Images',
			'Links' => 'Blog Roll',
		    );
     $translated = str_ireplace(  array_keys($words),  $words,  $translated );
     return $translated;
}

I checked everything, works great! Good luck with development ).