Document how XDM models and entities are internationalized

[trieloff]

We need to document how XDM models and entities will allow multi-lingual metadata to be defined for properties that are used to provide end user facing strings such as title and description.

JSON Schema has an open issue on how this might be achieved and JSON-LD defines how string internationalization should occur in their w3 spec.

I personally like the JSON schema proposal nest as it allows for the use of $ref to externalize the localized strings which will decouple the localization from the model definitions. Unfortunately, the proposal has yet to be accepted in to the JSON and the conversation in the issue seems to have trailed off over a year ago.

Once we align on the approach we'd like to take I'll open a PR with the documentation changes.

Thanks.

[lrosenthol]

There is now a W3C draft recommendation on how to address this. See https://w3c.github.io/string-meta/

[trieloff]

@lrosenthol I can see how we would use the string-meta approach within XDM, e.g. to localize product descriptions as outlined in #79. Would you also use it within the schema itself?

[cdegroot-adobe]

I like the syntax in Example #4
"title": [ "en": { "value": "Moby Dick", "lang": "en" },
"ar": { "value": "موبي ديك", "lang": "ar" "dir": "rtl"},
"ja": { "value": "白鯨", "lang": "ja" },
"zh-Hans": { "value": "莫比迪克", "lang": "zh-Hans", "dir": "ltr"} ],