Hi Hitoshi,
Your English is great and I know how it is to have to speak with subtlety in a second language, since I have to use a second language frequently and also worry that I sound too brusque when I am making requests.
I will definitely take your suggestion on board and consider the best way to integrate it in a future version, thank you for your suggestions. The most likely solution to the long unpunctuated speech question will just be to force a split on long unpunctuated text streams, since the lack of punctuation means there will be no contextual cues and the location of the split can be arbitrary (meaning: without any punctuation, we don’t know where the writer of the sentence meant to have clauses or emphasis, so we can split it anywhere because there is no better option). I’m not sure if I want to change the API to accomplish this goal but I will consider what you said.
To give you a preview for how I would be likely to do the long sentence splitting, I will probably implement an NSScanner to count incidents of whitespace between words and pick an arbitrary value that are “too many” spaces without there also being any punctuation or pauses, and insert a pause token before sending it to synthesis. So you could also use this as your workaround right now if you need this immediately.