How does a translator work?

One question interested me: how does a translator work, in which several languages. (like Google) For example, it is clear when the English-Russian, German-Russian French-Russian, there for every Russian word there are English, German, French analogues. Those. tied to the Russian word.
And when the translator from each to each, it is not clear what is attached. Maybe they invented some language to which other languages ​​are tied.
Somebody knows?