Can I Stop the Invisalign Treatment Early, Wear the Retainer Every Night, and Get Back on the Treatment Several Months After?

When Invisalign Aligners are not worn 22 hours a day, the tooth movement process is shut down, and leaving the trays out 3 hours may delay results three days.  Think of it as if an automobile manufacturer shut down the factory and laid off all the employees.  Then when it was decided to go back to manufacturing it would take a long time to recall all the employees and get the process up to speed.  

Wearing the aligner as a retainer for months at a time will result in stretching of the aligner, and you will lose some of what has been accomplished.  This may require a "Mid-course Correction" which is a significant added expense.  

You would be better off practicing reading aloud to minimize the aligners affect on your speech and getting past the treatment phase into the maintenance phase. 

Generally, interrupting Invisalign treatment is not advised and may result in relapse and the need for a new ClinCheck plan. Based on what you shared, you have an involved case as your refinement will extend treatment for a year. I have many college students, models, teachers and celebrities in active Invisalign treatment with few problems.  Your speech complaint should be addressed with your dentist as the trays may need to be modified to assist with your adjustment to them.

I understand what you are asking but in most cases this is going to cause more problems and delay treatment even more.  I would not recommend it but speak to your dentist about it and see what they have to say