What is an articulation disorder anyway?

According to the American Speech and Hearing Association (ASHA): "An articulation disorder involves problems making sounds. Sounds can be substituted, left off, added or changed. These errors may make it hard for people to understand you.Young children often make speech errors. For instance, many young children sound like they are making a "w" sound for an "r" sound (e.g., "wabbit" for "rabbit") or may leave sounds out of words, such as "nana" for "banana." The child may have an articulation disorder if these errors continue past the expected age."

Materials:
http://www.speakingofspeech.com/Articulation_Materials.html
http://speech-language-therapy.com/txresources.html
http://www.quia.com/pages/havemorefun.html

Parent Resources:
http://www.speech-language-development.com/articulation-therapy-ideas.html
http://mommyspeechtherapy.com/?p=687
http://www.pammarshalla.com/qa_topics.html#omc
http://www.asha.org/public/speech/disorders/SpeechSoundDisorders.htm

Tongue Exercises:
http://www.wearetbi.org/sahar2/discussions/286
http://wiebrecht.weebly.com/uploads/1/1/0/9/1109101/oral_motor_exercises.pdf
http://forestpark.kusd.edu/classrooms/redmon/documents/oral_motor_exercises1.pdf
http://www.brittonkill.k12.ny.us/walshweb/oral-motor_exercises.htm

Sound Development Chart: these are ages when sounds should be developed by: