The name derives from the fact that someone sending a telegram was generally charged by the word. To save money, people typically wrote their telegrams in a very compressed style, without conjunctions or articles. As children develop language, they speak similarly: when a child says "Water now!" it is understood that the child means, "I would appreciate a glass of water, immediately."
In the field of psychology, telegraphic speech is defined as a form of communication consisting of simple three or more word sentences usually comprising at least one noun and verb that adhere to the grammatical standards of the culture's language. For example, an English-speaking child would say "Give cupcake" to express that they would like a cupcake rather than "Cupcake give". Researchers have noted that this period of language acquisition occurs some time between the ages of 18–36 months and is present not just in English-speaking cultures, but can be found worldwide.
In adults, regression to telegraphic speech may indicate a neurological problem such as multiple sclerosis. Telegraphic speech is also common in non-fluent aphasia (Broca's aphasia), which is caused by a stroke damaging the posterior-inferior frontal lobe.
See also 
- Barker, S. (2004). Psychology (2nd ed.). Boston: Pearson Education.
- Bloom, L. (1970). Language development: Form and function in emerging grammars. Cambridge, MA: MIT Press.