English speakers don't use thou, except for a few rare people who have spent years studying older English dialects, like the King James Bible and Shakespearean plays. The use of thee, thou, thy and thine was already dying out when the King James Bible was translated in 1611. These words are still in the dictionary, so they can be confusing for speakers of languages that have two or more levels of formal and informal 2nd person, like tu/voce in Portuguese and tu/usted in Spanish. English only has one level for 2nd person: you, your, yours, and the slang plural forms like you all, y'all, you guys, you'uns, etc.
Without "do", it is extremely informal. It would not be considered correct in academic or professional English. It is only acceptable in casual conversation with friends or family. Questions in English normally have a main verb and at least one auxiliary/helping verb. The helping verb is before the subject, and the main verb is after the subject. A question may begin with a question word or the helping verb. It normally does not begin with the subject.
Don't feel bad. I am a linguist ("language scientist") with in-depth study of English grammar. Plus I studied the grammar of Spanish and Portuguese when I was learning them, including all the verb tenses. Most people don't know much about grammar. They are native speakers of their own language, so they just know what "sounds right."