speech on some topic vs speech in some topic

Some examples from the web:

• We knew you'd find out your daughter's original speech topic was Marie Curie.
• When I was 23, I was asked to deliver a speech on this very topic in front of an international group of young people who felt connected with this European ideal.
• I would ask the representative of the Council whether he thinks the President of the Commission's action was right and justified, and whether the Council also wants to restrict the Ombudsman's freedom of speech on this topic.
• Here are some topics that interest me: quantum mechanics, trains, flags...
• Some topics might even have to be excluded from the report in order to stick to a concise and sound text.
• It would be desired to keep this timing but we point out some topics in the report.
• Now ladies and gentlemen, we'll discuss some topic.
• So, professor, in addition to research I had requested, I allowed myself to deepen some topics and of course I brought entire bibliography... good.
• There will be competition between proposals both across and within research topic areas in this call, which may result in some topics not being supported.
• Some topics of the Work Programmes of this Priority are clearly devoted to children, for instance Medicines for children, or Rare autoimmune disorders: from genes to individualised medicine including paediatric diseases.
• The president makes his speech on Tuesday.
• Because this is my speech on civility.
• I wrote a whole speech on the plane.
• Maybe you want to practice your speech on me.
• And I also need somebody to do the obligatory thank-you speech on our behalf.
• Louise is making her maiden speech on Monday.
• I gave this speech on our wedding day.
• Watch his speech on the EP website on Thursday.
• I Cry reading that fine speech on your father.
• She was very gracious in her remarks about the speech on Tuesday in Portugal.

Some examples from the web:

• We knew you'd find out your daughter's original speech topic was Marie Curie.
• When I was 23, I was asked to deliver a speech on this very topic in front of an international group of young people who felt connected with this European ideal.
• I would ask the representative of the Council whether he thinks the President of the Commission's action was right and justified, and whether the Council also wants to restrict the Ombudsman's freedom of speech on this topic.
• Here are some topics that interest me: quantum mechanics, trains, flags...
• Some topics might even have to be excluded from the report in order to stick to a concise and sound text.
• It would be desired to keep this timing but we point out some topics in the report.
• Now ladies and gentlemen, we'll discuss some topic.
• So, professor, in addition to research I had requested, I allowed myself to deepen some topics and of course I brought entire bibliography... good.
• There will be competition between proposals both across and within research topic areas in this call, which may result in some topics not being supported.
• There's been kind of a series of epiphanies. The very next day, continuing a totally true story, I got on a G-5 to fly to Africa to make a speech in Nigeria, in the city of Lagos, on the topic of energy.
• The very next day, continuing a totally true story, I got on a G-5 to fly to Africa to make a speech in Nigeria, in the city of Lagos, on the topic of energy.
• rapporteur. - Madam President, Mr Šefčovič, many speakers start their speech in Parliament by saying that their topic is important, very important or even among the most important.
• General Abacha made a speech in Freetown this week.
• Some topics of the Work Programmes of this Priority are clearly devoted to children, for instance Medicines for children, or Rare autoimmune disorders: from genes to individualised medicine including paediatric diseases.
• I have already referred to her speech in Milan at Mario Monti's university, and on 17 February Mrs Kroes made another speech in Paris.
• As I told your interrogators, there are some topics I will only discuss with a Flag Officer
• It must also be recognised that certain aspects of this subject are highly complex in legal, technical and economic terms, and the initial positions on some topics appeared to be substantively very far apart.
• It was one speech in a movie.
• She's giving a speech in two hours.
• I have a speech in a few minutes.