My wife, who is from northern New Jersey, USA, and who has a cold, was looking for a box of Kleenex/facial tissues this morning; she said to herself, "I need those box of tissues." This was not simply a slip on her part; she's used similar constructions elsewhere—using "those/these X of Y" where X is singular and contains several instances of Y. Thus she may say "those box of tissues", "these bag of presents", etc. Her demonstrative adjective will agree in number not with the noun that it modifies, but with the object of the "of" phrase modifying that noun—but only in this situation, where "of" denotes containment.
Is there a well-studied dialect (one that, for example, is described in a language map of the United States) which uses a construction like this, or is this just her?
