Hi Juan,
Thank you for your feedback on our Speak feature! The “Speak” feature (or, so called “text-to-speech”) is trying to speak as natural as possible. So, its speed is as close as possible to that of a native speaker. It is true that for non-native
speakers, it might be too fast. Enabling users to control the speed of the Speak feature will certainly open up the possibility of using this feature for language learning purposes. We appreciate your feedback! Takako (Microsoft Translator
Team)