Changing placeholders

I’d like to change the placeholders for each of my three custom taxonomy filters.

I’m using your filter, but I set it to return $taxonomy:

function modify_dropdown_placeholder( $placeholder, $taxonomy ) {
    return $taxonomy;
}
add_filter( 'beautiful_filters_dropdown_placeholder', 'modify_dropdown_placeholder', 10, 2 );

That outputs my custom taxonomy slug in each of the filters. Is there a way to get it to output the custom taxonomy name instead?

(Sorry if this is remedial, but I’ve been reading the Codex for 2 hours and cannot figure it out.)