Beginning your talk in Japan with a series of apologies is standard practice. First apologise for speaking while standing, because you are towering above your audience implying superiority. Next, tell us how nervous you are about speaking to such a distinguished audience. Don't forget to mention you had no time to prepare the talk properly because you have been so busy. If you are sick, it is always good to get that in there too. If you are speaking in English then an apology for your poor English is manadatory. At the end, make sure you apologise for giving such a poor presentation.
Why do Japanese speakers go through all of this apologizing. Japanese humility demands a public display of rectitude. Appearing too confident is not appreciated. Seen to be a bit of a smarty pants never goes down well. Especially when most Japanese public speakers are untrained, dreadful, boring and killing us with their monotone it is always good to fit in rather than stand out.
So what should Japanese speakers do when they are addressing an audience in English made up of foreigners? What do we foreigners do when we are speaking to a Japanese audience in either Japanese or English?
Most talks are not remembered in much detail. What we do remember though is the speaker. We come away with either a positive or negative impression. Linguistic purity is not required in either case. Foreigners are used to non-native speakers giving presentations with accents, grammatical mistakes and unusual vocabulary choices. Japanese are basically convinced that non-Japanese can't speak Japanese so any attempt to do so is greeted with approval, as long as it isn't too perfect. Foreigners speaking perfect Japanese worries some Japanese who seem to think their protective barrier has been penetrated and maybe this foreigner knows a bit too much. A certain degree of ingorance is somehow more comfortable.
For Japanese speakers facing a Western audience open with a blockbuster that grabs everyone's attention and cuts through all the competition for the attention of your audience. Have some rhetorical questions at hand to keep the attention of your listeners. The audience should not know if they are going to be required to answer this or not to keep them locked in to th speech.
Have a proper close designed, in fact have two ready to go. One for before we get into Q&A and one for after questions. Don't just let the speech fade out, instead we need to leave our audience with a call to action to get them supporting whatever it is we are promulgating. The final close is to take back control of the speech, because questions are random and often can be completely unrelated to what it is we have been talking about. We need to re-state our main message so that this is what is ringing in the ears of our audience as they file from the room at the end.
For foreigners, don't copy the Japanese model because you are not Japanese, never will be considered Japanese and are not expected to be Japanese. Give the most professional presentation you can and be another speaker who the Japanese look at and wonder why they don't have those presentation skills.