You’ll need to remove the_title(); section from the following templates:
- content-aside.php
- content-featured.php
- content-gallery.php
- content-image.php
- content-intro.php
- content-link.php
- content-page.php
- content-quote.php
- content-single.php
- content-status.php
- content.php
Open the files and look for this:
<h2 class="entry-title">
<a href="https://wordpress.stackexchange.com/questions/33038/<?php
the_permalink(); ?>" title="<?php printf( esc_attr__( 'Permalink to %s', 'twentyeleven' ),
the_title_attribute( 'echo=0' ) ); ?>" rel="bookmark">
<?php the_title(); ?></a>
</h2>
The content will vary a little from template to template, just remove everything between the “entry-title” class to remove all titles from displaying in the pages.