Android (4.3+): Type Your Ringtone lets you set spoken notifications for individual callers in your contacts or for your favourite apps. If you want your phone to say "Simon is calling, sir" when he calls, or "You have a new message" when you get a text, this app can do it.
The video above is a quick demo of the app's features. You can set the language style, pitch, and speed of each alert, and you can customise contacts as well as apps, which is a nice touch. You can select from a variety of languages too, and preview any notification to listen and see if you like it before you save it. If you really like one, you can set it as the system notification sound as well. Of course, Android already lets you set specific notifications for each contact, but the nice thing about Type Your Ringtone is that you can just type in what you want your phone to say -- no uploading an audio file or anything.
The free version of the app is really just a demo of how it works -- you can create spoken-word alerts and set them as the system notification sound, but you'll have to upgrade to the $1.05 pro version to unlock the rest of the features and strip out the ads. Hit the links below to read more.