RECORD YOUR VOICE & COMPARE 
I've just added something to TextActivities.com that was actually a feature of my [no longer available] authoring software for Windows PC "TaskMagic" years ago.
It's the facility to record your voice and play it back so that you can compare your pronunciation with the model provided by the text-to-speech audio.
The student holds down the record button to record their voice and releases it to stop the recording. They can then play it back using the play button.
This works on all resources that have TTS audio controls enabled, including all sample resources and temporary student generated resources (accessed via the "study my own text" option).
It requires you to have a microphone available, obviously.
Let me know what you think 