Expose properties on TextRange for PowerPoint (office.js)

Using old interop I can access shape.TextFrame.TextRange.LanguageID. I see the preview of office.js for PowerPoint expose TextRange with a limited set of properties. Any plans to expose LanguageID or other missing properties?

Or if possible provide generic getters/setters as long as you known the property name of an object.

Reason I ask is that I have an old VSTO which sets the same language on all shapes, very useful in multi-national companies where multiple people edit a deck, leading to spell squigglies all over. And would be nice to use this in non-Windows versions of PowerPoint.