$list = array(
'apple',
'awesome',
'awards',
'bike',
'bbpress',
'nacin',
);
$current_letter = '';
foreach ( $list as $list_item ) {
$first_letter = mb_substr( $list_item, 0, 1 );
if ( $first_letter !== $current_letter ) {
echo 'Current letter is: ' . $first_letter;
$current_letter = $first_letter;
}
echo $list_item;
}