For the basic voice functionality, you do not need any new APIs. You continue to use the same existing PHP APIs, development and testing tools. VoicePHP will automagically give voice to all existing PHP APIs and language constructs.
For e.g.
echo "Hello World";
will speak "Hello World" instead of printing it
Since PHP by default is not designed for voice, we have added a few support APIs. For e.g. to make a call, one needs an API to do so. Similarly to record a message, we have added a record API and so on. These and the other support APIs can be accessed from the left pane