<?php

abstract class Person {

  abstract public function getName();

  public function getIntroduction() {
    return sprintf(
      __('My name is %s'),
      $this->getName()
    );
  }
}
// Person cannot be instantiated

class Manuel extends Person {

  public function getName() {
    return 'Manuel';
  }
}

// Manuel can be instantiated
$manuel = new Manuel();