At this time, we are only able to create English synthetic voices, but we do allow users to record a small number of non-English names and phrases as part of their custom sentences.
We are able to create voices of all English dialects, and in fact English speakers from all over the world have recorded ModelTalker voices (including users in Canada, the UK, Australia, New Zealand, India, South Africa, and Singapore). We should point out that the software has been particularly optimized for American English — particularly in the idiosyncratic pronunciations of words (think for example of the differences between American and British pronunciations of words like “controversy”, “garage”, “military”, and “herb”). Aside from this, users report finding that the resulting voice does a good job of capturing their accent as well as their voice quality.