title: Toward improved spectral measures of /s/: results from adolescents.
abstract: OBJECTIVE
  This article introduces theoretically driven acoustic measures of /s/ that reflect aerodynamic and articulatory conditions. The measures were evaluated by assessing whether they revealed expected changes over time and labiality effects, along with possible gender differences suggested by past work.
  
  
  METHODS
  Productions of /s/ were extracted from various speaking tasks from typically speaking adolescents (6 boys, 6 girls). Measures were made of relative spectral energies in low- (550-3000 Hz), mid- (3000-7000 Hz), and high-frequency regions (7000-11025 Hz); the mid-frequency amplitude peak; and temporal changes in these parameters. Spectral moments were also obtained to permit comparison with existing work.
  
  
  RESULTS
  Spectral balance measures in low-mid and mid-high frequency bands varied over the time course of /s/, capturing the development of sibilance at mid-fricative along with showing some effects of gender and labiality. The mid-frequency spectral peak was significantly higher in nonlabial contexts, and in girls. Temporal variation in the mid-frequency peak differentiated ±labial contexts while normalizing over gender.
  
  
  CONCLUSIONS
  The measures showed expected patterns, supporting their validity. Comparison of these data with studies of adults suggests some developmental patterns that call for further study. The measures may also serve to differentiate some cases of typical and misarticulated /s/.
authors.affiliation: Haskins Laboratories, New Haven, Connecticut, USA. koenig@haskins.yale.edu
authors.forename: Laura L
authors.initials: LL
authors.lastname: Koenig
authors.forename: Christine H
authors.initials: CH
authors.lastname: Shadle
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Preston
authors.forename: Christine R
authors.initials: CR
authors.lastname: Mooshammer
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D008046:Lip; D008297:Male; D010700:Phonetics; D012016:Reference Values; D012727:Sex Characteristics; D013060:Speech; D013061:Speech Acoustics; D014705:Verbal Behavior
keywords: acoustics; adolescents; development; speech production