There are 21 consonants in the English alphabet: B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Y, and Z. Consonants are speech sounds that are produced with a closure or narrowing of the vocal tract. They are used to create the structure of spoken language, and are important for distinguishing between words, for example, "cat" and "bat". Consonants can be voiced or unvoiced, and can be grouped into categories such as stops, fricatives, and affricates.