This article provides individual speakers' acoustic durational data on preboundary (phrase-final) lengthening in Japanese. The data are based on speech recorded from fourteen native speakers of Tokyo Japanese in a laboratory setting. Each speaker produced Japanese disyllabic words with four different moraic structures (CVCV, CVCVN, CVNCV, and CVNCVN, where C stands for a non-nasal onset consonant, V for a vowel, and N for a moraic nasal coda) and two pitch accent patterns (initially-accented and unaccented). The target words were produced in carrier sentences in which they were placed in two different prosodic boundary conditions (Intonational Phrase-final ('IPf') and Intonational Phrase-medial ('IPm')) and two focus contexts (focused and unfocused). The measured raw values of acoustic duration of each segment in different conditions are included in a CSV-formatted file. Another CSV-formatted file is provided with numeric calculations in both absolute and relative terms that exhibit the magnitude of preboundary lengthening across different prominence contexts (focused/unfocused and initially-accented/unaccented). The absolute durational difference was obtained as a numeric increase of preboundary lengthening of each segment produced in phrase-final position versus phrase-medial position (i.e., Delta(IPf-IPm) where 'f' = 'final' and 'm' = 'medial'). The relative durational difference was obtained as a percentage increase of preboundary lengthening in IP-final position versus IP-medial position, which was calculated by the absolute durational difference divided by the duration of the segment in phrasemedial position and then multiplied by 100 (i.e., (Absolute difference/IPm)* 100). This article also provides figures that exemplify speaker variation in terms of absolute and relative differences of preboundary lengthening as a function of pitch accent. Some theoretical aspects of the data are discussed in the full-length article entitled "Preboundary lengthening in Japanese: To what extent do lexical pitch accent and moraic structure matter?"[1]. (C) 2021 The Authors. Published by Elsevier Inc.
