To find how well children learn letter-sound correspondences when an orthography is highly regular, and how this ability relates to socioeconomic status (SES) and to reading ability, 240 Finnish children were tested for letter-sound generalizations. The test consisted of 25 synthetic words, constructed to look like Finnish words and to contain the full range of correspondences which occur in Finnish orthography. Children from Grades 1 through 3, stratified by sex and by SES, were tested individually on the word list, with the pronunciation of each word being scored either right or wrong. An analysis of variance on the raw scores showed a significant grade effect at the .01 level, but no SES or sex effect. Mean correct, however, was almost 80% in Grade 1, indicating a surprisingly high level of letter-sound mastery. But the correlations of letter-sound ability with reading ability were only moderately high, ranging from .528 (Grade 2) to .487 (Grade 3). This result indicates that the ability to generalize letter-sound correspondences does not guarantee high ability in reading. (Author)