Little Voice Commander is a toy program for young toddlers who are just learning to start to speak. The program runs full screen (across multiple monitors if present) and listens for a child to speak or press a key. If the program detects something being spoken, it finds the best match for a word it has photos for, and displays some random photos for that word, as well as the word text. If a key on the keyboard is pressed, a word beginning with the pressed key is displayed, along with some photos for that word. Users can add their own photos easily, so you can customize it with pictures of mom, dad, sister, brother, dog, cat, house, etc. It will scan labeled photos on startup and add those words to its vocabulary.
It uses the microsoft speech recognition engine, which is ok but not ideal. I wouldn't expect to be able to use this to teach any kid how to pronounce words -- it's more to encourage very young kids to babble and give them the experience of having what they speak affect what it shown in a semi-consistent manner.