Wrong German voice for English book

**Description**

From a recent discussion on https://internetarchive.slack.com/:

I [...] tried the BookReader with another one (https://archive.org/details/josephus0001jose_d9c3/page/189/mode/1up) [..] BookReader used German pronounciation for the English text. That sounds horrible. I was not able to understand anything.

BookReader uses a German voice for the English book above (now confirmed for Firefox and Safari), but when I try the example which is suggested in the BookReader webpage (http://www.archive.org/stream/birdbookillustra00reedrich), I get a male English voice.

**Expectation**

I'd expect an English voice for the first book, too, as both books are English. Maybe BookReader is confused because the first book also has Greek text parts?

**Context**

My tests were done on macOS with Firefox and Safari.