  One of the established multi-lingual methods for testing speech
intelligibility is the matrix sentence test (MST). Most versions of this test
are designed with audio-only stimuli. Nevertheless, visual cues play an
important role in speech intelligibility, mostly making it easier to understand
speech by speechreading. In this work we present the creation and evaluation of
dubbed videos for the Oldenburger female MST (OLSA). 28 normal-hearing
participants completed test and retest sessions with conditions including audio
and visual modalities, speech in quiet and noise, and open and closed-set
response formats. The levels to reach 80% sentence intelligibility were
measured adaptively for the different conditions. In quiet, the audiovisual
benefit compared to audio-only was 7 dB in sound pressure level (SPL). In
noise, the audiovisual benefit was 5 dB in signal-to-noise ratio (SNR).
Speechreading scores ranged from 0% to 84% speech reception in visual-only
sentences, with an average of 50% across participants. This large variability
in speechreading abilities was reflected in the audiovisual speech reception
thresholds (SRTs), which had a larger standard deviation than the audio-only
SRTs. Training and learning effects in audiovisual sentences were found:
participants improved their SRTs by approximately 3 dB SNR after 5 trials.
Participants retained their best scores on a separate retest session and
further improved their SRTs by approx. -1.5 dB.
