Insert Custom Pause Duration for Text to Speech Content!

Hi,

I am using the TTS feature on my iPhone to have Siri read step-by-step instructions while complex physical tasks are being performed. Great for students learning to perform complex tasks while their sight must be directed to the task at hand, or while moving about which would make looking at a screen impossible. Is there a way to add custom pauses in TTS so that the student can receive the instruction and have time to perform it during the pause, with the ability to custom design the length of each pause to accommodate completion of tasks which require varying amounts of time to complete, before the next step in the instruction is announced?