Here are some good developmental norms I have found…  

This chart is from the Goldman Fristoe Test of Articulation (GFTA)- 2nd Edition.  It seems to be the most accurate from my experience.  However, there are several varying norms for articulation out there.  This chart, nonetheless, should give parents a general idea of what to expect from their 2-7 year olds!  Initial, medial and final refers to the placement of that sound in a word. For example, a word that has “b” medial would be “trouble”.

Here is a chart that I found from Mommyspeechtherapy.com.   This is a great chart that breaks down the phonological processes that should be eliminated and by which age!  Phonological processes are patterns of articulation errors.  These errors are usually more significant and frequently occurring in children’s speech, making it more unintelligible.  Examples of each “process” is listed, as well!

Here is an awesome guide full of developmental norms—got this from Linguisystems  Linguisystems Developmental Norms

This is a very basic chart for language…Basic Language Norms_Birth to 6years

Additionally, here is a basic look at cognitive norms up until 5 years old.  Often times, those who have cognitive delays or deficits may also manifest language difficulties.  Cognitive Milestones_ Birth to 5

Here’s a basic look at social skills milestones.  This gives a great idea on if your student/child is on track for age-appropriate social skills.  Speech therapy is very appropriate and useful for working on these skills as needed!  Social Skills Milestones