Hello! I am American as well as the other person commenting. I don’t mean to confuse you with contradictions, but I have heard this many times. In fact, my family and I use this very often. To start “Ought to” is in fact a word in the English language and is proper. It is a modal verb almost always followed by “to”. As the other person said, you should use “should” instead as it is more common now. But something interesting about “ought to” is that it is more commonly said fast here in the New York/New Jersey region and transformed into our speaking as “ought ta” (it sounds like awe-tuh). This “oughtta” is heavy slang but is used by many people here. An example with the proper “ought to” would be: -They ought to be done by now! This is a very common phrase in English. Remember that saying “oughtta” is slang and not proper English that is said commonly. Rather we can see that “Ought to” is proper and can be used but is uncommon to say phonetically and fully in a sentence. Hence why we get the jumbled slang “oughtta”. But this is the fun part of language! Learning to bend and break the rules which often helps us learn within the constrictions of language. It’s fun! Keep up the good work! Very good question! Best, -Giancarlo