"Was redest du da?"
(literally, "What are you talking there?")
This phrase is commonly used in informal settings to express mild surprise or curiosity about what someone is saying. It can also convey disbelief or suspicion, depending on the tone of voice used.
Here are some additional German phrases and expressions you can use to ask related questions:
Wovon redest du?
(literally, "What are you talking about?")
This phrase is similar to "Was redest du da?", but it is generally more formal and respectful.
Was meinst du damit?
(literally, "What do you mean by that?")
This phrase is used to ask for clarification or elaboration on a specific statement.
Was ist los?
(literally, "What is going on?")
This phrase can be used to ask about a general situation, or to express surprise or confusion.
Was hast du gesagt?
(literally, "What did you say?")
This phrase is used when you didn't hear someone clearly or want them to repeat something.