The German particle ''ja'' is used to indicate that a sentence includescontains information that is obvious or already known to both the speaker and the hearer. The sensesentence ''Der neue Teppich ist rot'' means "The new carpet is red". ''Der neue Teppich ist '''ja''' rot'' may thus mean "As we are both aware, the new carpet is red", which would typically be followed by some conclusion from this fact. However, if the speaker says the same thing upon first seeing the new carpet, the meaning is "I'm seeing that the carpet is obviously red", which would typically express surprise.
