Consonants are speech sounds that are produced by obstructing the airflow in some way as it passes through the vocal tract. This obstruction can be caused by the lips, tongue, teeth, or other parts of the mouth. Consonants are contrasted with vowels, which are produced without any obstruction to the airflow. In English, the consonants are the sounds represented by the letters B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, and Z.