To change the ‘read more’ text in a child theme of Twenty Ten, one needs to add a few lines to functions.php of the child theme.
This procedure uses a method that I came across in an introductory article about programming a child theme of Twenty Ten, by Aaron Jorbin, who himself was building upon Mangling strings for fun and profit, by WordPress lead Developer Peter Westwood.
class Transformation_Text_Wrangler { function reading_more($translation, $text, $domain) { $translations = &get_translations_for_domain( $domain ); if ( $text == 'Continue reading <span class="meta-nav">→</span>' ) { return $translations->translate( 'Get to know more <span class="meta-nav">»</span>' ); } return $translation; } } add_filter('gettext', array('Transformation_Text_Wrangler', 'reading_more'), 10, 4);
This way of customising texts in a child theme is applicable to all the strings of the mother theme.