Mine was also imageless and English-only. I imaging this device just stores the raw text, with perhaps some short formatting codes, which would save space over full HTML pages. (Not all that much, however, given that both versions are compressed.)
Wikipedia is *huge*; just the raw English articles in pure HTML really do take up some 200GB in uncompressed form. I actually had to create a loopback filesystem image to hold it, as my normal root filesystem, created with the default settings, didn't even have enough inodes for that many files.