Depending on the cloud storage your created speech files are saved on your cloud storage accounts when you connect a cloud storage i.e. DropBox, Amazon S3, Google Drive and select those cloud storage when you create a file.
When you connect your DropBox account it will create a folder named "NewscasterVocalizer" inside the Apps folder on your DropBox account. You can find your created files inside that NewscasterVocalizer folder.
Here is the directory unless changed or modified:
My Files > Apps > NewscasterVocalizer
If you create a bucket for NewscasterVocalizer and add that bucket name when you connect your Amazon S3 account in NewscasterVocalizer, your files will be saved inside that bucket.
Or, if you left the Bucket name blank, it will automatically create a bucket for NewscasterVocalizer with a file name like "newscaster-some numbers" and save your files inside that bucket when you use Amazon S3 storage during your file creation.
When you connect your Google Drive it will automatically create a folder named "Newscaster App" in your Google Drive. When you use Google Drive to create your files, they will be saved inside that Newscaster App folder.