Abstract We demonstrate Open CALL-SLT, a framework which allows non-experts to design, implement and deploy online speechenabled CALL courses. The demo accompanies two long papers [1, 2] also appearing at the SLaTE 2015 workshop, which describe the platform in detail

Cathy Chua

Claudia Baur

Manny Rayner

Nikos Tsourakis

Pierrette Bouillon

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An Open Platform That Allows Non-Expert Users to Build and Deploy
Speech-Enabled Online CALL Courses (demo description)
Manny Rayner, Claudia Baur, Pierrette Bouillon, Cathy Chua, Nikos Tsourakis
University of Geneva, FTI/TIM/ISSCO, Geneva, Switzerland
Abstract
We demonstrate Open CALL-SLT, a framework which allows
non-experts to design, implement and deploy online speech-
enabled CALL courses. The demo accompanies two long pa-
pers [1, 2] also appearing at the SLaTE 2015 workshop, which
describe the platform in detail.
1. Content
Open CALL-SLT is a platform that has been under development
at Geneva University since mid-2014 and is currently in alpha
testing; it builds on ideas developed in the earlier CALL-SLT
project [3, 4], but amounts to a complete redesign. The primary
goal of the new framework is to support rapid construction of
multimodal speech-enabled online language-learning resources
by non-expert users. The basic form of a CALL-SLT course is
spoken multimedia prompt/response: the system issues a multi-
media prompt, the student responds using speech, and the sys-
tem either accepts or rejects, possibly giving additional feed-
back on a rejection. This allows the student to practise both
pronunciation and productive competence. The platform can be
accessed both on normal browsers and on Android devices; the
screenshot in Figure 1 illustrates the user interface. Recognition
uses course-specific grammar-based language models compiled
from the course descriptions, which offer accurate feedback to
students. Measured on recorded data collected from a large
evaluation carried out with Swiss German school students in
2013/2014 (15 classes, 200 students, 43K logged interactions;
[5]), we estimate that the system rejects utterances annotated as
linguistically incorrect about five times as often as those anno-
tated as linguistically correct [2] .
In order to accommodate a wide range of potential course
designers, functionality is organised in six levels of increas-
ing sophistication. The simplest levels assume only basic web-
literacy, and essentially amount to speech-enabled multimedia
flashcards; the prompt consists of a piece of text and an optional
piece of multimedia (an audio file, JPEG, MP4 or similar), and
the course designer explicitly lists possible responses. Higher
levels add functionality that requires acquaintance with some
basic concepts from computer science: minimal versions of
templates, regular expressions and context-free grammar make
it possible to write more elaborate sets of prompts and re-
sponses, a simple XML-based scripting language allow the de-
signer to link up prompts into interactive multimodal dialogues,
and a score/badge system supports gamification of the courses.
Courses are uploaded to a set of shared servers, where they
can be remotely compiled, tested and deployed. The main tech-
nical challenge is to minimize the probability that one user’s
content can break the system for other users. This is addressed
by arranging deployment in a number of stages; the user starts
by compiling new content on its own and is only allowed to add
it to the shared resources when it has compiled correctly.
Figure 1: Screenshot showing CALL-SLT user interface.
A tutorial introduction and reference can be found in the on-
line documentation [6]. Examples of Open CALL-SLT courses
can be freely accessed at http://callslt.unige.ch/
demos-and-resources/.
We will demo courses developed using the platform as well
as the process of remotely modifying and redeploying a course.
The current alpha testing phase is scheduled to finish shortly be-
fore the date of the workshop, and we are interested in meeting
people who may want to participate in beta testing.
2. References
[1] M. Rayner, C. Baur, C. Chua, P. Bouillon, and
N. Tsourakis, “Helping non-expert users develop online
spoken CALL courses,” in Proceedings of the Sixth SLaTE
Workshop, Leipzig, Germany, 2015.
[2] M. Rayner, C. Baur, C. Chua, and N. Tsourakis, “Super-
vised learning of response grammars in a spoken CALL
system,” in Proceedings of the Sixth SLaTE Workshop,
Leipzig, Germany, 2015.
[3] M. Rayner, P. Bouillon, N. Tsourakis, J. Gerlach,
M. Georgescul, Y. Nakao, and C. Baur, “A multilingual
CALL game based on speech translation,” in Proceedings
of LREC 2010, Valetta, Malta, 2010.
[4] M. Rayner, N. Tsourakis, C. Baur, P. Bouillon, and J. Ger-
lach, “CALL-SLT: A spoken CALL system based on gram-
mar and speech recognition,” Linguistic Issues in Language
Technology, vol. 10, no. 2, 2014.
[5] C. Baur, M. Rayner, and N. Tsourakis, “Using a serious
game to collect a child learner speech corpus,” in Proceed-
ings of LREC 2014, Reykjavik, Iceland, 2014.
[6] CALLSLT, Writing CALL-SLT Lite Courses, http:
//www.issco.unige.ch/en/research/projects/LiteDocSphinx/
build/html/index.html, 2015, as of 10 April 2015.
Show&Tell Contribution SLaTE 2015, Leipzig, September 4–5, 2015
183 Copyright c© 2015 ISCA


An Open Platform That Allows Non-Expert Users to Build and Deploy Speech-Enabled Online CALL Courses (demo description)

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An Open Platform That Allows Non-Expert Users to Build and Deploy Speech-Enabled Online CALL Courses (demo description)

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