Most pediatricians today agree that it is not something to stir up anxiety other than to deal with it and ensure that the children have a proper language model to speak to early and often in their young lives. Parents who both work long hours should attempt, through their exhaustion, to spend time speaking and reading to their kids. In the case where the idioglossia has already developed, it's important that a parent speak clearly and slowly and pronounce syllables carefully so that the child can repeat them correctly.

It is, after all, important for the child's own self-esteem, that he or she learn proper language skills so that the awkwardness of the "twin-speak" can be overcome before they reach...

"Autonomous Languages of Twins." Acta Genet Med Gemellol (English) (1987): 233-238.
Goodhart, J. And G. Still. The Diseases of Children J.A. Churchill, 1905.

Neer, Katherine. "How Twins Work." n.d. HowStuffWorks.com. 7 May 2009 .

Thomas, Joy. Idioglossia: A Review and Some Observations. Information Analysis - Research. ERIC database: Accession #: ED252287, 1979.

"Twin Language Uncovered." 2007. Twin-Pregnancy-and-Beyond. 8 May 2009 .

TwinsMom. "Their Voices Emerge." 21 April 2009. Troupsburg.com. 7 May 2009 .