Document Type

Theses, Ph.D


Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence


Computer Sciences

Publication Details

Sucessfully submitted for the award of Doctor of Philosophy to the Technological University Dublin in June 2009.


The focus of this research is on oral communication between L1 (first language) and L2 (second language) English users - to determine whether an algorithm which slows down speech can increase the intelligibility of speech between interlocutors for EIC (English for International Communication). The slow-down facility is a CALL tool which slows down speech without tonal distortion. It allows English language learners more processing time to hear individual phonemes as produced in the stream of connected speech, to help them hear and produce phonemes more accurately and thus more intelligibly. The study involved five tests, all concerned with the intelligibility of English speech. The first test looked at L2:L2 English communication and levels of receptive intelligibility, while Tests 2 and 3 focused on testing the slow-down for receptive communication – to help L2 users to process speech by slowing it down and thus making the speech signal more accessible. Tests 4 and 5 changed focus, testing the slow-down speech tool as a means of enhancing the intelligibility of L2 speech production, namely individual phoneme production, as little research has been carried out in this area and phoneme discrimination can greatly increase the intelligibility of an L2 speaker’s pronunciation. Test 5, the main test, used a qualitative analysis of a pre- and post test and a number of questionnaires to assess subjects’ progress in developing intelligible English phoneme production across three groups: the Test Group, who used the slow-down speech tool, the Control Group, who undertook similar pronunciation training but without the application of the slow-down tool and the Non-Interference Group, who received no formal pronunciation training whatsoever. The study also ascertained and evaluated the effects of other variables on the learning process, such as length of time learning English, daily use of English, attitudes to accents, and so forth.