Published online: Aug 1, 2022Purpose: This scoping review considers the acoustic features of a clear
speech register directed to nonnative listeners known as foreigner-directed
speech (FDS). We identify vowel hyperarticulation and low speech rate as the
most representative acoustic features of FDS; other features, including wide
pitch range and high intensity, are still under debate. We also discuss factors
that may influence the outcomes and characteristics of FDS. We start by
examining accommodation theories, outlining the reasons why FDS is likely
to serve a didactic function by helping listeners acquire a second language
(L2). We examine how this speech register adapts to listeners’ identities and
linguistic needs, suggesting that FDS also takes listeners’ L2 proficiency into
account. To confirm the didactic function of FDS, we compare it to other
clear speech registers, specifically infant-directed speech and Lombard
speech.
Conclusions: Our review reveals that research has not yet established whether
FDS succeeds as a didactic tool that supports L2 acquisition. Moreover, a complex
set of factors determines specific realizations of FDS, which need further
exploration. We conclude by summarizing open questions and indicating directions
and recommendations for future research.This research was supported by a Doctoral Fellowship
(LCF/BQ/DI19/11730045) from “La Caixa” Foundation
(ID 100010434) awarded to Giorgio Piazza and by the
Spanish Ministry of Science and Innovation through the
Ramon y Cajal Research Fellowship (RYC2018-024284-I)
awarded to Marina Kalashnikova. This research was supported
by the Basque Government through the BERC
2022-2025 program and by the Spanish State Research
Agency through BCBL Severo Ochoa excellence accreditation
CEX2020-001010-S. This research was also supported
by the Spanish Ministry of Economy and Competitiveness
(PID2020-113926GB-I00 awarded to Clara D. Martin)
and by the European Research Council under the European
Union’s Horizon 2020 research and innovation programme
(Grant Agreement 819093 awarded to Clara D.
Martin)
