Are public speeches in The Crown accurate?

The Crown tries to present a dramatisation of Queen Elizabeth's rise into power (or rather, the early years, at least in the first two seasons, I am aware that it will jump into a later period in later seasons).

Many scenes include speeches which would be very public, e.g. Churchill's eulogy or the Christmas speeches, or things which makes one move uncomfortably in their seat like the speeches in Kenya and the Bahamas, etc.

While I am certain that the sentiments are true to form, are they really taken from history, or are they part of the dramatisation?

In other words, I am sure that the private conversations between different characters are made up, perhaps with some basis in reality, or at least some extrapolation. But what about the public addresses? Are those taken verbatim, or dramatised, or completely rewritten for the story?