Modals

[Mauricio67]

When do I use " Shall" ,and "ought to"?

Thanks

Mauricio.

[Anglika]

I shall answer this = I intend to answer this
We shall give you an answer soon = WE intend to answer soon

["Shall" is increasingly being replaced by "will" with I and We, but is still used; see this for more information: AskOxford: shall ]

I ought to answer this = it is desirable/necessary that I answer this
We ought to go home = it is desirable that we go home

[riverkid]

OUP:

USAGE Strictly speaking shall should be used with I and we to form the future tense, as in I shall be late, while will should be used with you, he, she, it, and they, as in she will not be there. This, however, is reversed when strong determination is being expressed, as in I will not tolerate this , and you shall go to school. In speech the distinction tends to be obscured, through the use of the contracted forms I’ll, she’ll, etc.

I don't think that this is an accurate description even for BrE.

M-W

Shall

usage From the reams of pronouncements written about the distinction between shall and will—dating back as far as the 17th century—it is clear that the rules laid down have never very accurately reflected actual usage. The nationalistic statements of 18th and 19th century British grammarians, who commonly cited the misuses of the Irish, the Scots, and occasionally the Americans, suggest that the traditional rules may have come closest to the usage of southern England. Some modern commentators believe that English usage is still the closest to the traditionally prescribed norms. Most modern commentators allow that will is more common in nearly all uses. The entries for shall and will in this dictionary show current usage.

va=shall - Definition from the Merriam-Webster Online Dictionary

AHD

the traditional rules. The traditional rules state that you use shall to show what happens in the future only when I or we is the subject: I shall (not will) call you tomorrow. We shall (not will) be sure to keep in touch. Will, on the ...

the reality. The English and some sticklers about usage are probably the only people who follow these rules, and then not with perfect consistency. In America, people who try to adhere to them run the risk of sounding pretentious or haughty. Americans normally use will to express most of the senses reserved for shall in British usage. Americans use shall chiefly in first person invitations and questions that request an opinion or agreement, such as Shall we go?, and in certain fixed expressions, such as We shall overcome. In formal style, Americans use shall to express an explicit obligation, such as Applicants shall provide a proof of residence, though must or should works just as well here. In speech you can get the distinctions in meaning delineated in the traditional rules by putting stress on the auxiliary verb, as in I will leave tomorrow (“I intend to leave”). You can also choose another auxiliary verb, such as must or have to, that is less open to misinterpretation, or you can make your meaning clear by adding an adverb such as certainly.

§ 56. shall / will. 1. Grammar. The American Heritage Book of English Usage. 1996

[Anglika]

Ah well, some people just don't like the Oxford English Dictionary.

[banderas]

Ah well, some people just don't like the Oxford English Dictionary.

But Mauricio67 will certainly be happy about so many sources

[Anglika]

Here's another : Learning English | BBC World Service

and another: Shall and Will. Fowler, H. W. 1908. The King's English

and another: The Difference Between “will” and “shall”

[riverkid]

and another: Shall and Will. Fowler, H. W. 1908. The King's English

The Decline of Grammar

G Nunberg

Take Modern English Usage, by that good man H. W. Fowler, "a Christian in all but actual faith," as the Dictionary of National Biography called him. Despite a revision in 1965, it is out-of-date, yet it still has a coterie as devoted as the fans of Jane Austen or Max Beerbohm, ...

#

[Anglika]

It is still worth reading him. He has a good sense of humour.

[riverkid]

Here's another :
The Difference Between “will” and “shall”

You can trash this one too. He suggests; "... For the long answer, take a look at Fowler (Modern English Usage) and the OED."

[riverkid]

It is still worth reading him. He has a good sense of humour.

But you shouldn't offer him up to ESLs or anyone for that matter as an authority on the English language, Anglika.

Now on the shall/will thing. It isn't a matter of "liking" Oxford. There is a great deal of good stuff in there but when they repeat nonsense like this, that's a different matter.

For shall, BrE, conversation, the LGSWE notes that its frequency is in the 300 per million words range while will is around 5500 per million words.

For NaE, shall barely registers, 5-10 per million while will is around 4800 per million. Given these numbers, for both dialects, with the frequency of "I/We will's" in the language, I think it unlikely that this "rule" is followed much at all.