Finnish is a language with simple syllable structure but rich
morphology. It was investigated whether syllables or morphemes are
preferred processing units in early reading. To this end, Finnish first-
and second-grade children read sentences with embedded inflected target
words while their eye-movements were registered. The target words were
either in essive or inessive/adessive (i.e., locative) case. The target
words were either non-hyphenated, or had syllable-congruent or
syllable-incongruent hyphenation. For the locatives, the
syllable-incongruent hyphenation coincided with the morpheme boundary,
but this was not the case for the essives. It was shown that the
second-graders were slowed down by hyphenation to a larger extent than
first-graders. However, there was no slowdown in gaze duration for
either age group when the syllable-incongruent hyphen was
morpheme-congruent. These findings suggest that Finnish readers already
utilize morpheme-level information during the first grade.