I was having a problem in WordPress for my blog where the title contained duplicate values, like “John’s blogJohn’s blog”.

The fix for me was to edit wp-content/themes/twentyeleven/header.php and disable a bit of the output, as shown below. I basically just added an if ( false ) to disable the code which caused the duplicate content.

This seems to effectively mean that Yoast SEO is in charge of the titles now. You can configure separately the homepage, posts, and pages titles in the Yoast SEO settings. I configure mine in Yoast SEO Settings / Content Types like this:

Homepage

Site title Separator Tagline

Posts

Title Separator Site title

Pages

Title Separator Site title

<title>
<?php
  // Print the <title> tag based on what is being viewed.
  global $page, $paged;

  wp_title( '|', true, 'right' );

// 2024-07-14 jj5 - OLD: I removed this because wp_title() (above) does everything that needs to be done.
if ( false ) {
  // Add the site name.
  bloginfo( 'name' );

  // Add the site description for the home/front page.
  $site_description = get_bloginfo( 'description', 'display' );
  if ( $site_description && ( is_home() || is_front_page() ) ) {
    echo " | $site_description";
  }

  // Add a page number if necessary:
  if ( ( $paged >= 2 || $page >= 2 ) && ! is_404() ) {
    /* translators: %s: Page number. */
    echo esc_html( ' | ' . sprintf( __( 'Page %s', 'twentyeleven' ), max( $paged, $page ) ) );
  }
}
?>
</title>