You could say that TinyTalk is the simple, basic, austere and minimal version of the famous Skype. It is effectively an Internet phone, to communicate orally with another computer through the IPs of each of the computers.
The operation of TinyTalk is very simple, you just have to specify the IP of the computer you want to connect to. Once connected to that IP you can start transmitting (logically both teams need both microphone and speakers).
Despite being a very basic tool, TinyTalk has some interesting features such as pausing automatically if for a few seconds there is no oral activity between the computers, storing the IPs of the computers to which you connect most regularly, etc.
You can free download TinyTalk 32, 64 bit and safe install the latest trial or new full version for Windows 10 from the official site.