From this site:
An electronic larynx (electrolarynx), is a battery operated machine that produces sound for you to create a voice. There are many different makes and types, but they are usually about the size of a small electric razor.
How to use it
You hold the machine against your neck, or fit a small tube into the corner of your mouth. When you press the button on the machine, it makes sound. If you move your tongue and mouth you can form the sounds into words.
The electrolarynx might be the best speech method for you in case: •you cannot have a voice prosthesis (TEP) for medical reasons •you did not have a voice prosthesis put in at the time of your surgery, but you are waiting to have one put in later
Assuming that there is an eruv allowing you to carry this, and assuming that it has been turned on before Shabbat, are there any problems using this device on Shabbat or Yom Tov? E.g. any problems such as using electricity / battery; creating a circuit; causing electric circuits or lights to blink while speaking, etc.?