There is one important difference that sets Microsoft apart from the other three companies, though. While Apple, Google and Facebook have pledged to pause get contractors to transcribe recordings, it looks like Microsoft will still continue with the exercise.
Instead, the company has updated its privacy policy to mention that it will indeed have humans review some recordings. On balance, The Verge says that it is possible to retroactively delete your voice data. This can be done by going through its privacy dashboard. It looks like Microsoft is making a stand regarding its recording of clips to improve Cortana and Skype Translate. It remains to be seen if Apple, Google and Facebook will be making an about turn with their earlier decision, now that Microsoft has set a precedent. (Source: Motherboard, Microsoft [1], [2], [3], [4] via The Verge)