I checked the dialogues.json.
I checked it through NotePad and Visual Studio.
But I don't think there's a dialogue for each chapter.
It consists of only one line and seems to be missing a lot of content.
Did I miss anything?
If you're using Notepad, make sure you turn on the 'Word Wrap' feature under the 'Format' tab, it makes things easier. At a first glance, the file might seem like a jumbled mess of random stuff, but if yours is like mine, sitting at over 2,100kb in size, then I can assure you it's the correct file. You only need to tell code from strings in order to translate the information that needs to be translated (it usually comes after 'val:').
If all of the text is showing up as one line, I'd recommend opening the dialogs.json file in an editor with a json formatter. For example, you can use Sublime text, with the Pretty JSON package: https://packagecontrol.io/packages/Pretty%20JSON
But if you don't want to deal with installing and using a new editor, probably the quickest thing to do is find a web-based json parser from among the numerous ones that will pop up if you google search for "json parser" or "json formatter," like one: https://jsonformatter.org/json-parser Then upload the dialogues.json file, hit the "format JSON" button, and then download or copy it back into your editor. The result should give you something like this: 
Hopefully that helps!