Access email over phone call

Description

We are looking to build a new email access platform that allow our customers to get access to their emails over a phone call and they will be able to fetch new emails, read emails over a phone call by using the system text to speech and they can reply, forward, delete or mark spam by using speech to text and also writing their emails reply by using dictation via a phone call and then the dictation will be converted to text by using speech to text.
Our system will be based on an email server which will provide the pop3 email access to the phone system in order to fetch the new emails and allow the customer to control their emails by reply, forward, delete or mark as spam by selecting options on the phone keypad or by voice commands.
Each customer will have an email account on the email server and will be able to access the email address by placing a call to the phone system (based on Asterisk pbx).
Each customer will use an authenticate method to authenticate and allow the access to email account through the phone system.
We will provide the development virtual machines to be used as development environment as will as provide any other tools and assistance that will help to build this project.
We will also provide the development environment and tools for the telecom phone system that will act as the tool that will provide the phone call access to the email platform.
The project must be provided as open source code.
Any other recommendation and suggestions are highly appreciated and accepted.