l10n question, seeking po files, and proper l10n procedure for this software.

I have volunteered to localize gnewbook.org, an elgg based site, base in Latin America.

It looksl like they put the site up, editing the php files to add Spanish strings, by hand, or something.  Most of their site is in Spanish, with some parts in English.  They sent me, rather than po files, all their php file, some of which are still name, for instance, en.php, while containing Spanish strings.

Also, their site configurations seem to offer about 5 languages, (in the user configuration panel, just as here, there are 2, English and German), however altering this configuration does nothing, and their site is still mostly in Spanish, with some parts still in English.

Nonetheless, in their php files, I'm also finding some French and German strings.

I generated a po file from what they sent me, and still, I have source strings in Spanish, English, German, French....

I thought I was going to be translating their Spanish to English, and then coordenating localization to other languages from there.

What I'd like is to simply have a source po file in one language from which i can work into others.

Are there source po files available for this software from elgg?

Are there already localizations available ni other languages?

Where do I find info.documentation, etc. on how to correctly localize their site, so that altering the language in user configurations is productive?  

I'd like to, at least, have a full spanish version and a full english version, in stead of the mess they have now, which is a mixture.  From there I can move on to other languages.