  In forensic voice comparison the speaker embedding has become widely popular
in the last 10 years. Most of the pretrained speaker embeddings are trained on
English corpora, because it is easily accessible. Thus, language dependency can
be an important factor in automatic forensic voice comparison, especially when
the target language is linguistically very different. There are numerous
commercial systems available, but their models are mainly trained on a
different language (mostly English) than the target language. In the case of a
low-resource language, developing a corpus for forensic purposes containing
enough speakers to train deep learning models is costly. This study aims to
investigate whether a model pre-trained on English corpus can be used on a
target low-resource language (here, Hungarian), different from the model is
trained on. Also, often multiple samples are not available from the offender
(unknown speaker). Therefore, samples are compared pairwise with and without
speaker enrollment for suspect (known) speakers. Two corpora are applied that
were developed especially for forensic purposes, and a third that is meant for
traditional speaker verification. Two deep learning based speaker embedding
vector extraction methods are used: the x-vector and ECAPA-TDNN. Speaker
verification was evaluated in the likelihood-ratio framework. A comparison is
made between the language combinations (modeling, LR calibration, evaluation).
The results were evaluated by minCllr and EER metrics. It was found that the
model pre-trained on a different language but on a corpus with a huge amount of
speakers performs well on samples with language mismatch. The effect of sample
durations and speaking styles were also examined. It was found that the longer
the duration of the sample in question the better the performance is. Also,
there is no real difference if various speaking styles are applied.
