There appears to be some degree of uncertainty about the accentuation of final demonstratives in the literature. According to Wells, “this, that, these and those tend to convey new information and attract the nucleus”. Carr, however, holds a different view, affirming that they “count as function words, so they do not take the tonic when the LLI rule applies”. Let’s compare a couple of examples given by them:
(298) 
I’d like some of those, please (Wells).
(299) Can I have five of those? (Carr)
Of course the examples are not the same and five is a much more accentable word than some, but the fact remains that both authors don’t agree on this matter.
Judging from the examples collected for this work, it seems reasonable to assert that final demonstratives are quite likely to be deaccented on a great number of occasions. Actually, many times they could be substituted with the pronoun it with no change of meaning at all. Let’s consider this:
(300) I didn’t know about it.
(301) I didn’t know about that.
On the other hand, it also is true that final demonstratives can be accented for emphatic purposes.
(302) I didn’t know about that!
Which possibility prevails it might be difficult to say for sure. The examples gathered here are sorted out in two different groups. In the first one, final demonstratives are deaccented. In the second, they bear the nucleus. Interestingly the former clearly outnumber the latter, and, for what is worth, I should say that the reason for this imbalance is that they were much easier to find.
- Final demonstratives deaccented
(303) I don’t think anybody can deny that (Jonathan Bate; Kent, UK).
(304) Can you develop that? (Melvyn Bragg; Carlisle, Cumbria, UK).
(305) So, probably it makes its way into style without you having to make a big effort for that (Colm Toibin; Enniscorthy, Ireland).
(306) Any book worth its salt will be something much larger than that (Richard Flanagan; Tasmania, Australia).
(307) Do we have any idea of him sitting down and saying now I will do this (Melvyn Bragg; Carlisle, Cumbria, UK).
(308) How would you respond to that, Imogen? (Laurie Taylor; Liverpool, UK).
(309) I suppose so, I never really thought about that (Dennis Price; Berkshire, UK).
(310) Before I do that / there’s something I want to talk to you about (Frank Alberston; Fergus Falls, Minnesota, US).
- Final demonstratives accented
(311) I know that (john Nettleton; London, UK).
(312) Anthony is not like me. You can say that again (Hugh Laurie; Oxford, England).
(313) I’m sorry to hear that (Philip Loeb; New York, US).