This paper reports investigations of the extent to which novice readers (Grades 1 and 3) and adult readers used different types of letter-sound units when reading aloud. Although differences in performance of children and adults were observed, all age groups used grapheme-phoneme units more frequently than they used bodies. Both children and adults were better at reading nonwords constructed from real word-bodies than at reading nonwords whose bodies did not exist in English words, except that Grade 1 children derived significantly less benefit from word bodies than did older readers. Word reading accuracy showed that these differences between Grade 1 and older readers were not attributable to unfamiliarity with the words containing the body units. Beginning readers can apply grapheme-phoneme correspondences by the end of Grade 1. Their skills improve so that accuracy in reading monosyllabic nonwords in Grade 5 is only slightly below adult performance. The contribution of body-level units increases from Grade 2 onwards, and is likely to be due to expansion of the orthographic input lexicon.