I have exactly the same problem. My Microsoft Lumia 950XL Windows 10 is downloading one speech language and the other is pending already 3 days. I cant do anything to stop it or cancel it. It does not complete the download-I have tryid everything,except "restore factory settings". I am sure that it would be the only way to stop the neverending downloading and pending, but I do not want to reset my phone-I have wasted some much time on setting it my way. Please fix this bug in next update !