The Internet is rich with information relating to speech and language development and difficulties.
The following websites and documents are recommended, providing further information
Bowen, C. (1998) Ages & Stages Summary: Language Development 0-5 Years.
Speech Pathology Australia (2015) The Sounds of Speech: 0 to 3 years
Speech Pathology Australia (2015) The Sounds of Speech: preschool and school aged children.
Speech Pathology Australia (2015) What is a Speech Pathologist?
http://www.speechpathologyaustralia.org.au/library/2013Factsheets/Factsheet_What_is_a_SP_web.pdf
Speech Pathology Australia (2013) Frequently asked questions about Speech Pathology services.