By 3 years of age, a child should be pronouncing many different consonant sounds, such as p, b, m, w, t, d, n, g, h, and y. The child should also be putting together simple sentences, although they may make simple mistakes like, “I goed to playground.” If your child is making these kinds of mistakes, the advice is not to make them say the sentence correctly. Instead, acknowledge what your child has said with the correct verbiage, “You went to the playground? How fun!” They should also be clearly articulating the final consonant in a word, such as “mop.”
Between the ages of 2 and 6, you child may begin developing a particular kind of stutter that is known as developmental disfluency. Remember, between these ages, your child’s vocabulary is exploding. Their minds are often working faster than their mouths can keep up. If your child is saying things such as, “I, um, um, um, um, and then completes the sentence correctly, there is generally no cause for concern. However, if the stuttering does not improve, or worsens, an evaluation might be considered.
Between ages 4 and 6, your child should now have added the sounds for h, sh, ch, j, z, l, and v. However, the sh, ch, and j sounds may be replaced with the s, z, t, or d sound. For example, a child may say ‘ship’ as ‘sip.’ They may also replace r sounds with the w sound. For example, “rabbit” may be “wabbit.” Sounds for words like the “th” in thank you may be pronounced with the f sound as “fank you.”
By age 7, your child may still be saying “thank you” as “fank you” or with as “wiv” and there are no real sound pronunciation milestones. However, by age 8, your child should be able to pronounce all speech sounds with no noticeable errors.
If you would like a chart detailing specific speech and articulation milestones, the American Speech-Language-Hearing Association has speech development charts separated by ages here.