chang_comment_text.php

<?php

function my_give_comment_text_switcher( $translations, $text, $domain ) {
	// changes the "Donations" text in multiple places
	if ( $domain == 'give' && $text == 'Comment' ) {
		$translations = __( 'TITLE', 'give' );
	}

	// changes the "Make this Donation [monthly/weekly/daily]"
	// text for a donor's choice recurring checkbox
	if ( $domain == 'give' && $translations == 'Leave a comment' ) {
		$translations = __( 'YOUR TEXT HERE', 'give' );
	}

	return $translations;
}
add_filter( 'gettext', 'my_give_comment_text_switcher', 10, 3 );