> Are you planning to add this app on iOS?
The development of this application on the Android environment is already taking me a lot of time. Starting the development of this application on the iOS environment is not conceivable for me at the moment.
> I have bought the Pro version of the application, but I can't download it. What can I do?
If you just purchased the application, you may have to wait a few hours to be able to download it, depending on how long it takes Google to validate the transaction.
If you purchased it a few days ago and still can't install it, what you can try to do is remove the cache of the PlayStore application.
> I have added the transcription for a word, but the app isn't using this information for the audio.
The transcription field allows you to add additional information on a word. This can't be used for audio, simply because there is no Text-to-speech system handling this kind of information (yet).