Sorry if I wasn’t clear enough, but the article does address your question in a couple of different ways.
First, option one is the $49 Aeon doorbell. This can play up to 99 different sounds, and you can upload your own custom sound files. So that’s really all you’d need. You can have it play a speech file or a chime or whatever when the door is opened as long as you have a sensor on the door to capture the opening event. So that’s the one which is probably going to be the fastest and easiest way to do what you were asking about. The door opens, a custom audio Notification plays. It’s very popular. And you can have different notifications play for different events, again with a limit of 99 maximum different ones.
Option 4 is a general statement that you can do this if you have a specific TTS device. But that’s talking about devices that have a text to speech feature built-in, like Sonos. I don’t think that’s really a good fit for your particular situation, although it might be if you happen to have one of those devices.
Option 5 in the article is the one that applies directly to your question in a way that you were suggesting in the first place. It’s just using an android device instead of a laptop. It has a link to the community discussion on LANnouncer, which is an app which will let you do this on any android device. So you can just get an inexpensive android phone or tablet and use that to play the sounds.
You can also use the quick browse lists and look for smart apps for alerts to control when the various sound files are played.
You might want to just try this one. It’s very popular and can work with a number of different devices, including the LANNouncer App which is also linked to from the original wiki article.
But I do think most people will choose option one from the wiki article, the Aeon doorbell. It’s inexpensive, it works well, and it integrates well with SmartThings. Once you follow the links to the community discussions, you’ll find that there are existing device type handlers and smartapps that will allow you to easily set up a sensor trigger for individual sound tracks on the device.