These are some ideas for things to work on/look at when your child is approaching his third birthday. Don't get too hung up on any one item, try to look at your child's speech from a wide view when they are really little (birth to 3). For very young kids how they are using the words they have (language) is more important than how they are saying the words they have (articulation).
Children should be able to copy the “m”, “b”, “y”, “n”, “w”, “d”, “p”, and “h”
Children might be able to copy the “t”, “ng”, “k”, “g”, “f”, “v”, “ch”, and “j”
Children should use be using correct vowels in their words
Children should be able to say the sounds listed above in the beginning and endings of words (if they are alone and not in a group of consonants).
Children might not be able to say all of the consonants that are in a group (like the st in stop)
Children might replace a hard sound like a “v” with an easier sound like a “b”
Children should be talking with 3 or 4+ words in a phrase, expressing ideas, commenting, and requesting help.
Strangers should be able to understand around 75% of what child says (gestures included)
Parents should be able to understand around 90% of what child says (gestures included)