Using "ought" in a question: "Ought I celebrate?" or "Do I ought to celebrate?"

Question

How do I ask a question using ought?

• Ought I congratulate him? (like in this post)
• But I ought to congratulate is easily turned into Do I ought to congratulate, just like I have congratulate becomes Do I have to congratulate, and in Ought I congratulate? the to is dropped.

Do I ought to appears to have significantly less usage, e.g. from Google Ngram. Is it grammatically incorrect? Why?

Answer 1

Do I ought to is non-standard and is never found in formal writing or speech; it may be found occasionally in informal speech, but even there it is dialectal or sub-standard.

Ought is in most respects a modal auxiliary verb like must, can and may, and shares with them the following characteristics:

• It is defective—that is, it lacks certain forms which ordinary (lexical) verbs have: it has no infinitive, no past or present participle, and no -s for the 3rd person singular present.
• It is negated with simple not rather than with do not: You ought not (to) do that.
• It may be inverted with its subject to form a question: Ought I (to) do that?

It differs from most other modal verbs in two respects:

• Like must, it has no distinct past inflection (and for the same reason: historically it is the past form of its parent verb owe).
• In positive indicative clauses it is used with a marked infinitive (to VERB) rather than the bare infinitive (VERB): You ought to do that. In negative clauses and questions the to is often, but not always, omitted.

Accordingly, the proper form for your question is:

Ought I congratulate him? OR Ought I to congratulate him?

The use of ought is decreasing, and is mostly confined to declarative sentences now. It has been largely replaced by should. For this reason, actual on-the-ground use is somewhat erratic, particularly with regard to the presence or absence of the to marker; negative and interrogative uses just aren’t used enough to ‘fix’ their forms firmly in people’s speech habits.

Answer 2

Ought I… definitely is a more common usage, and easier on the ears. I have encountered that many a time in literature. And, as you had probably seen, Do I ought… is not even found by Google Ngrams.

The OED actually has a clarification, noting that the modal verbs behave differently from regular verbs:

The verb ought is a modal verb and this means that, grammatically, it does not behave like ordinary verbs. In particular, the negative is formed with the word not alone and not also with auxiliary verbs such as do or have. Thus the standard construction for the negative is he ought not to have gone. The alternative forms he didn’t ought to have gone and he hadn’t ought to have gone, formed as if ought were an ordinary verb rather than a modal verb, are found in dialect from the 19^th century but are not acceptable in standard modern English.

Further there is more about forming the negative:

The negative form of verb phrases containing ought is formed simply by adding not: you ought not to go and see the doctor. It is not standard English to use didn't ought to.

However, in the definition above there is an example of usage in a way modal verb would be used in a question:

What ought I to do?