A 5 year old can "Comprehend" more then we want to believe. 

However, children do need to learn words directly through explicit instruction in order to comprehend oral and written text. "Readers cannot understand what they are reading without knowing what most of the words mean. As children learn to read more advanced texts, they must learn the meaning of new words that are not part of their oral vocabulary" (National Institute for Literacy, 2001, p.