This paper focuses on Partial and Synchronized Caption (PSC) as a tool
to train L2 listening and introduces new features to facilitate
speech-related difficulties. PSC is an intelligent caption that extensively
processes the audio and transcript to detect and present difficult words or
phrases for L2 learners. With the new features, learners can benefit from
repetition and slowdowns of particular audio segments that are automatically
labeled difficult. When encountering high speech rates, the system slows
down the audio to the standard rate of speech. For disfluencies in speech
(e.g. breached boundaries), the system generates the caption and repeats
that video segment. In our experiments, intermediate L2 learners of English
watched videos with different captions and functionalities, provided
feedback on new PSC features, and took a series of tests. Smart repetition
and slowdown components received positive learner feedback and led to
significant improvement in L2 listening recognition.
Facilitating L2 listening through automatic detection of speech and
lexical difficulties
