This is, IMNSHO, a Really Bad Idea™.
As seen in the example given by @James Curran: if the dictionary/translator mangles even a simple, gramatically correct sentence, how will it fare in translating a typo-ridden, ambiguous, "plz send teh codez" text from Elbonian? My money would be on "crash and burn spectacularly" - the result will have an even lower SNR than the broken English we sometimes see here.
This is rooted in deeper, more abstract issue, which is only partially programming-related: Every once in a while (in the case of Stack Exchange, about three times a year, depending on the weather on the interblags), some programmer looks at a dictionary and thinks "hey, this translation thing should be easy - after all, everyone thinks in the same language, the languages just encode that, right?" Wrong. While that's a useful model of computer behavior (Turing-equivalence and all that), in stark contrast to programming languages, natural languages are not encodings of a universal brain-language, common to humanity.
The language is partially the medium, partially the message itself - thus, thinking in English will actually make you think in a different way than thinking in German or Polish or Japanese. This is one of the reasons why translation is hard - even in the simplest case of humans translating technical texts. Yes, there are tricks that make dictionary-based "translations" (like Google Translate's "transcribe words using a dictionary") sort-of work, and humans can - with effort - work out the meaning thereof, but the result won't be a translation, not by a long shot.
Just for a laugh, this is my second sentence, written in gramatically correct Czech (my native language), and then passed through the translator: "If the compiler and maim so simple sentence, how goes the full text hrubek, uncertainties and 'send-code-please' from elbonštiny?" The meaning is just about recognizable if you compare it with the version written in English, but almost unintelligible on its own - and that is from a gramatically correct input, from one Indo-european language to another.
Although this site is trying to be as user-friendly as possible, this proposal IMO wouldn't help - at best, it would shift the task of parsing out the meaning completely to the readers, with minimal help from the askers; at worst, it would actively lower the SNR by injecting meaningless gibberish (as it will mistranslate and/or give up on uncommon words; that's not to mention edit wars that tend to break out over side-by-side miltilingual content).
Please don't construe this as "English is the One True Language [of the Net]" or "questions must be gramatically perfect or perish" - I just think that SO cannot be, and shouldn't try to be, everything for everyone in every language which gives perfect results regardless of the user's effort. Being a great, English-language Q&A site for professional and enthusiast programmers is a large enough goal, without adding another layer of complexity - worse, a layer that has never worked right and probably won't in the predictable future.