Drupal - l() function with HTML and class.
<?php
$options = array(
'html' => TRUE,
'title' => t('SOME TITLE'),
'attributes' => array('class' => array('button color medium'))
);
$output['content'] = l(t('Schedule an appointment'), 'node/8', $options);
?>
<?php print l('<span>' . t('MY TITLE') . '</span>', 'myurl', array('html' => TRUE, 'title' => t('SOME TITLE'), 'attributes' => array('class' => 'myclass'))); ?>