Books written to help improve the reading skills of children should be ahead of their understanding by an increment that is readily attainable. The first books in large print with lots of colourful pictures must necessarily be in simple language and employ a limited vocabulary. These are intended to be read with the aid and encouragement of a sympathetic adult: a teacher, parent or older sibling. With the passing of time, more and more reading is done alone, but the acquisition of new words continues apace, understood from context or by referral to an adult or a dictionary. What is needed to drive this process is writing that turns pages and cannot easily be put down.
Children acquire their mother tongue by hearing it spoken and learning the meaning of words from the context in which they are used. The process goes on for some years before the child starts asking the meaning of new words, and by this time the words have become longer, rarer and more technical. The same progress is made with reading. Many new words are picked up almost unconsciously by the avid reader while others require recourse to a dictionary, and the process continues throughout adult life as anyone who has read the novels of Vladimir Nabokov will testify.
The most important function of a children’s book for silent reading is to entertain; the educational function must be well concealed. There are various means by which new words can be introduced. The English language contains many synonyms and their use can avoid the unattractive repetition of the same word. In such cases, the general meaning of new words should be immediately apparent, although understanding subtle shades of difference may take longer and involve further reading. Some categories of words are eagerly absorbed by children and these can be used to awaken broader interests. Jargon, related to new developments in communication, sport and popular science, is readily acquired, and the characteristic speech of particular communities or historical periods can also be used to introduce new words.
At one time, it was common for adults to address children using only words and phrases that they expected the hearer to know, but nowadays such talking down is much less common. Many teachers and parents make a habit of addressing children and adults alike, expecting a question if something is not understood. Authors need to take more account of the age of their readers, to avoid too great a level of difficulty, but the underlying aim to stretch the young mind is the same.