Other uses of “imperative prohibition” form eg わかるな ・すわんな

Question

I saw a film where in two separate scenes the characters seemed to use the "imperative-prohibition" to invite the opposite action:

1.In one scene a father after explaining something to his son appeared to ask his son if he could understand what he had explained:

「わかるな」？

It was as if he had said: 「[おれのいうこと]、分かりませんか」？

2.In another scene a woman invited a child to sit on a chair that she was pointing at:

「すわんな」

As if she had said: 「座りませんか」

In both cases I am sure I have quoted the subtitles correctly but is this really the imperative prohibition or have I missed something?

Answer 1

I think in that context, that わかるな？ uses sense 3 of this entry at Daijirin to "seek agreement or a response". It might be similar to わかるよね？ ("you understand, right?")

I think すわんな would be a more colloquial form of 座りな/座りなさい "sit down". I think な here is a shortened form of なさい to make a command as in this entry. Note this is different from the prohibitional 座るな "don't sit".