Computer generated feedback on vowel production by learners of English as a second language

Abstract

The acquisition of new vowel sounds is one of the most challenging tasks for the adult learner of a second language. It is also an aspect which requires a great deal of time and individual attention. Learners of English are particularly hampered by the irregular orthographic representation of vowel sounds. This paper reports on research in progress into the development of an application to provide learners with real time feedback on their vowel production. This process includes the calculation and plotting of formants on a graph using the PRAAT programme. The patterns which result are highly reminiscent of the traditional vowel chart, which in turn reflects articulation, i.e. articulatory changes are reflected on the graph. This application can provide feedback on both pure vowels and diphthongs. Some of the difficulties and obstacles which as yet prevent it from being a tool which can be used by the learner autonomously will also be outlined and discussed. Foremost amongst which are: the question of speaker normalisation (how to compensate for the difference in values between male, female and pre-pubertal speakers) which may be resolved by way of statistical elaboration of the formant data; and the methods used to isolate the vowel sound from the rest of the signal.