Nick_Pyner:
You are calling Software serial but not using it, hence nothing on bluetooth.
Nick gave you the answer.
Serial.print is the hardware serial print command and prints to the TX pin.
BTserial.print is your software serial print command and prints to the pin 9 which you have defined. You are not using
BTserial.print („example serial text“);
anywhere in your code.
Take the troubleshooting step by step. First, completely independently of your glove sketch, make sure that serial to Bluetooth is working.
Use the example sketches for your bluetooth module as a starting step. You can also try hardware serial.
Use your PC bluetooth first. Then there are also bluetooth serial terminal apps for android. Use these for testing baud rates etc.
Make sure that the baud rate in your sketch, in the bluetooth module and in your TTS app match.
P.S. Side note: the setup in the youtube video is not really a useful product, in my opinion.
It actually only recognizes finger straight/finger curved. It works so badly, that the user has to use the other hand to curve the finger. It repeats words over and over. The gestures are not really sign language, they are made up. Real gestures also involve movements and positions of the whole arm. So I question the point of the whole exercise. Sorry to be so negative 
So, if this is an actual application, and not a pastime exercise, I suggest some buttons will be much easier to handle for you and the user