The role of different orthographic units (letters, syllables, words) in reading of orthographically transparent Finnish language was studied by independently manipulating the number of letters (NoL) and syllables (NoS) in words and pseudowords and by recording eye movements during repeated reading aloud of these items. Fluent adult readers showed evidence for using larger orthographic units in (pseudo)word recoding, whereas dysfluent children seem to be stuck in a letter-based decoding strategy, as lexicality and item repetition decreased the NoL effect only among adult readers. The NoS manipulation produced weak repetition effects in both groups. However, dysfluent children showed evidence for word-specific knowledge by making fewer fixations on words than pseudowords; moreover, repetition effects were more noticeable for words than pseudowords, as indexed by shortened average fixation durations on words due to item repetition. The number of fixations was generally reduced by repetition among dysfluent children, suggesting familiarity-based benefits perhaps at the perceptual level of processing.