Whenever we work on a PO file, we usually translate from English to the translate language. However, recently at OLPC, we had some Aymara translators who did not know English, but were quite comfortable with Spanish. We had been receiving such requests for supporting the display of an intermediate language in our translation system for quite some time now, and it was also a prominent feature request for Pootle, the web based translation software that we use. I was feeling a bit bored with my usual work, and decided to see if I could do something.
The straight forward way of implementing the feature would be to add yet another user preference which would store the list of languages in which the user would want to see the translations, but that seemed to involve significant amount of coding, and I was too lazy to do that. After thinking for sometime, I decided to take a short cut which should help us quite nicely now. Pootle can optionally show it’s interface in a non-English language, and I thought I would take advantage of that. Within around an hour (which included figuring out some of the Pootle code and understanding jToolkit), I had a patch which produced this:

So, if you select your UI language as Spanish, along with the original msgid, you will also get the corresponding Spanish translation when you are translating a message. I think this should do for now - though the “proper way” is probably the right thing to implement at some point.