asterisk call id

https://wiki.asterisk.org/wiki/display/AST/Unique+Call-ID+Logging+in+Asterisk+12+and+beyond

asterisk hangup handler

https://wiki.asterisk.org/wiki/display/AST/Hangup+Handlers

FreePBX custom extension

[from-internal-custom]
exten=>_100,1,Answer()
same=>n,Playback(hello-world)

Google Speech API

https://cloud.google.com/speech/docs/languages
https://cloud.google.com/speech/docs/basics
https://github.com/GoogleCloudPlatform/php-docs-samples/blob/master/speech/quickstart/quickstart.php
https://cloud.google.com/speech/docs/getting-started
https://cloud.google.com/speech/docs/basics
https://cloud.google.com/speech/docs/reference/libraries#client-libraries-usage-php
https://cloud.google.com/speech/docs/
Interactive guide

https://codelabs.developers.google.com/codelabs/cloud-speech-intro/index.html?index=..%2F..%2Findex#0


quick

https://cloud.google.com/speech/docs/reference/libraries



translation

https://cloud.google.com/php/docs/reference/


default credentials
https://github.com/google/google-auth-library-php
https://developers.google.com/identity/protocols/application-default-credentials