Oral language development is a key outcome of elementary school, and it is important to identify factors that predict it most effectively. Commonly researchers use ordinary least squares regression with conclusions restricted to average performance conditional on relevant covariates. Quantile regression offers a more sophisticated alternative.…

Speech productions of 40 English- and 40 Japanese-speaking children (aged 2-5) were examined and compared with the speech produced by 20 adult speakers (10 speakers per language). Participants were recorded while repeating words that began with "s" and "sh" sounds. Clear language-specific patterns in adults' speech were found,…