You may create a budget for a GCP project to avoid surprises on your bill and monitor all of your Google Cloud Platform charges from one place. With a budget, you can create alerts that send emails to your billing administrators when charges exceed a certain amount.
If you would like to control your environment relative to your budget, then you can use programmatic budget notifications to automate your budget actions. Here, you can find an example on how to disable billing to stop usage.
At the moment, I couldn’t find any tool to show you the character usage, however you may send us your request on this feature so that the Cloud Text-to-Speech API will evaluate your request.
Here, you can find the Google Support Group for Cloud Speech discussions. Furthermore, you may report any bug including the bugs related to the documentation via the Issue Tracker (under Speech API issues category) as well.
you can use programmatic budget notifications to automate your budget actions. Here, you can find an example on how to disable billing to stop usage.
Here, you can find the Google Support Group for Cloud Speech discussions.