At that time, children can produce short sentences, although they use telegraphic speech – sentences that sound as if they were part of a telegram, in which words not critical to the message are left out. Rather than saying “I showed you the book”, a child using telegraphic speech may say, “I show book”, and “I am drawing a dog” may become “Drawing dog”. As children get older of course, they use less telegraphic speech and produce increasingly complex sentences.
Telegraphic speech is the form of speech used by children of 18 months to 2 years of age where only the key words in a phrase are used (with the 'ifs' , 'ands' and 'buts' missed out).