Microsoft has launched the first phase of its Skype Translator preview program for Windows 8.1 users, along with people who have installed the Windows 10 Technical Preview. Those folks who have signed up for the preview can download an app that is designed to translate both written and spoken languages in real time. Skype Translator was first announced in May.

Microsoft says, "The preview program will kick-off with two spoken languages, Spanish and English, and 40+ instant messaging languages." It added:

This is just the beginning of a journey that will transform the way we communicate with people around the world. Our long-term goal for speech translation is to translate as many languages as possible on as many platforms as possible and deliver the best Skype Translator experience on each individual platform for our more than 300 million connected users.

The official Skype blog has more technical details on how Skype Translator works. It states

Skype Translator's machine learning protocols train and optimize speech recognition (SR) and automatic machine translation (MT) tasks, acting as the glue that holds these elements together. This "glue" transforms the recognized text to facilitate translation. This process includes the removal of disfluencies (i.e. 'ahs' and 'umms' as well as re-phrasings), division of the text into sentences, as well as addition of punctuation and capitalization.

Source: Microsoft