Embedding Property

The Embedding Property is the following property described by Hoemai :

A core syntactic property of Toaq is that you can take any clause and embed it, as is, inside ꝡä. I would be sad to give up this property.

If X is a grammatical clause, then ꝡä X should be a grammatical complementizer phrase. Informally, anything you can do in the main clause should be possible in a subclause.

This chiefly relates to underfilling: if we say underfilling verbs is allowed in the main clause (Chuq nháo.) but not in subclauses (ꝡä chuq nháo), that violates the Embedding Property. (The question is: can we somehow (a) allow underfilling, (b) uphold the Embedding Property, (c) prevent ambiguous subclause boundaries and (d) avoid terminators, all at once?)