When calling a phone number one sometime falls on a voice mail. I sometimes prefer to leave text messages than voice mail messages, but some phone numbers don't accept text messages.
I am looking for an Android program that can take a written text as input and takes care of leaving a message on the voicemail through text-to-speech conversion. Free of charge. Less preferable but still OK: web service or Windows/Linux program. I'm mostly interested in the United States (i.e. both sender and recipient in the United States).
Some carriers offer this service, but it is not free:
Sending a text message to a landline is just like sending a standard text message. Just create a text message from your Sprint phone and address it to a 10-digit phone number. Your text is converted to a voice message, which is automatically read to the recipient when he or she answers the phone. If the recipient does not answer the phone, your text message is stored as a voicemail, provided the recipient has voicemail service on their landline phone. Your recipient can also reply to your message. Effective July 1, 2014, each text message to a landline will cost $0.25. Customers will be required to opt-in before being charged for sending a text to landline.
Some web services offer this service, but I haven't found any free one:
Easily integrate Text to Speech messages into your app, CRM software or website and send a voice message to any phone in the world, landline or mobile. 1000 SMS cost $17. Web interface or API.