According to the Goldman-Fristoe Test of Articulation-3rd Edition, an industry standard for evaluating speech sound disorders, the following are some basic guidelines for when 85% of children tested could produce a sound correctly at the beginning position in a word: 2 years: B, D, H, M, N, P
3 years: F, G, K, T, W
4 years: KW
5 years: CH, J, L, S, SH, Y, BL
6 years: R, V, BR, DR, FL, FR, GL, GR, KL, KR, PL, ST, TR
7 years: Z, SL, SP, SW, TH