In spoken informal Japanese, the question particle か is often dropped entirely, and a question is instead indicated simply by a rising intonation at the end of the sentence.

When asking a question in informal speech with a noun or a な-adjective, you cannot use the informal copula だ before か. Saying だか is grammatically incorrect for direct questions. You must drop だ and attach か directly to the word. Additionally, using か directly after a plain noun or な-adjective can sound blunt or masculine, so it is often omitted entirely in favor of using just a rising intonation.