You can't say this: "You do like this?" because the emphasis with "do" works only in a statement: "I do like this" = "I really like this". This question can't be reduced and the word order can't be changed. Omitting functional words and breaking word order are 2 different things. Word order must be fixed. In this one: "You don't want something?" you can say: "want anything?"

Thx for the answers!

Hello Kirill, "You don't want something?" Does not make sense out of context. However if the word 'don't' is stressed in this sentence, it is sometimes used to reiterate a question already asked. For example if you ask a person 'Do you want something to eat?' and they give a response that appeared negative but was unclear, you might then say 'You DON'T want something?' to make sure that you understood them correctly. The same with "You do like this?". If you want to emphasise "do" then you would have to use this sentence after you had already asked someone as a checking method. For example, 'I made you a cake but I don't think you'll like it', the recipient of the cake then eats it and enjoys it so you say in a shocked tone with emphasis on the "do", "You DO like this?' These forms are often used in spoken English but only as a secondary check of information. I hope this helps:)

The title of the question is a bit confusing, as it suggests you are asking about omission, but I think all you are asking if it is possible to ask a question without using the 'reversed' word order. In your examples "You don't want something." and "You do like this." are both simple statements of fact. They can easily be turned into yes/no questions by adding a question tag such as "don't you?". You are familiar with this, aren't you? In speech we can also change a statement into a yes/no question by using a combination of: stress on the verb (on the auxiliary if there is one), a rising tone, and other cues - facial expression, gestures etc. We only tend to do this in situations of 'surprise' and emotional tension where there is little doubt of questioning intent. For example, if I gave you a bowl of ice cream but noticed a look of disgust on your face, I might equally say "You DO like ice cream?" or "You DO like ice cream, don't you?". Note also that I would mostly use 'anything' rather than 'something' in questions such as yours.