Negative contractions in a question

Question

I know how negative contractions are used, and that they're all pretty straightforward in informal writing.

Didn't she go to the opera with you?

Weren't you a pastor before, Jacob?

Can't we get in trouble for this?

But I feel like the tones or meanings of these questions change when the contractions aren't used. Like the second one:

Were you not a pastor before, Jacob?

It almost sounds accusatory, in a facetious way. As if to imply Jacob had done something to contradict his prior lifestyle. The third one doesn't even sound correct when being used that way.

Does this tone-shift occur because of how we use the contractions in modern times? And in the instance of the third example, are they all still correct even when they don't seem like it?

Answer 1

Each of your sentences, even the third one, can be said with or without the contraction. When it's possible to use the contraction, but not is used instead, it becomes emphatic: it implies that we really believe or expect the positive to be the case.

To express your third phrase without the contraction, one might say:
"How can we not get in trouble for this?"

Without the preceding how, it may sound odd because can we not is commonly used to express something we want, or, depending upon the stress, intonation, and context, something we don't want.

Expressing desire not to go:
"I don't like movies by that director. Can we not go to the movie?"

Expressing desire to go:
"I love this director. Can we not go to the movie?"

I found a short transcript describing this form and its ambiguity: http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/1837_aae/page30.shtml