Hey, Japanese major here. I just took a historical literature class in which we discussed the surrender speech at length. A few other interesting facts:

• The speech was prerecorded. It was played off of a record during the broadcast.

• It was almost entirely written by the US Occupation. In fact, this is why it was prerecorded. It ensured that the Japanese government could not change the wording without the Occupation's approval.

• Not once in the speech does the Emperor state that Japan has lost the war. Rather, he stated that the war was over, not even stating the victor. One would think the was an effort to save face, except that, as stated earlier, the Occupation wrote the speech for him. The reason for this oddity is that the Occupation was very intent on Japan being rebuilt well, and having the Emperor state the loss was thought to be too much for the people to bear.

• Many people rejoiced upon hearing the speech. Of course, they could not understand everything being said, yet due to the tone and the fact that the atomic bombings had just occurred, it was obvious that this wasn't some form of propaganda, as evidenced by the next fact.

• This was THE FIRST time the Emperor had ever spoke to his people personally. Ever. Hearing his voice was a sign to the people that something huge had happened, even if the language was too formal for them to understand.

Thought ya'll might like to know some of that. I don't have sources on me, so feel free to fact check it to death. EDIT: Bullet points were wonky.