In fact, you can’t use the
Syntax.preform file yet. You have to include bits of Preform in the extension directly, like this:
[Your Preform here.]
-) in the Preform grammar.
Your best bet it to look at another translation (French, Spanish or Italian) and “port” them to Japanese. This document also describes how Preform works and what all its sections do. (But not all the Preform described in it works when directly included in an extension. It’s best to only use the parts that are used in the linked extensions.)
An other important thing you have to know is that the adaptive verbs do not work in the latest version of Inform (6M62) because of a bug and only work in 6L38. The Spanish and Italian extensions have removed this functionnality so that they work on 6M62, but I prefered to stay in 6L38 for French.
If you decide that you want your translation to work with 6M62, you’ll have to manually write standard text substitutions for each verb used by the responses and at every tense and viewpoint.
Something else : using Preform for verbs with Japanese may not work at all because I don’t think Inform supports Unicode in the source (only in the texts), so you won’t be able to write Japanese characters in text substitutions. It may therefore be better to go with manually writing substitutions for the verbs.
(There may be more issues in some other Inform 7 features regarding Unicode, especially in the Inform 6 inclusions, but workaround should exist.)
It’s quite a lot if information, I agree, especially since it’s a part of Inform that’s not that documented. Don’t hesitate to ask more question, I’ll gladly help. I’m always happy when someone tries to translate Inform in another language!