It's also necessary for us to know
a.) What platform (phone, Windows, Linux, Mac...) and/or b.) On the web or desktop?
With the answer to these questions you should be able to easily find out for yourself what language to use, as it seems you have no preference. How fast you want the translations to happen matters because it will tell you how low level of a language you're going to want.
If you're doing it on the web I would give PHP a shot as your main weapon, with the regular open web technologies for client side (JavaScript, HTML, CSS... just building the page).
If you're going for a Windows desktop application, I would use C# because I consider it relatively easy to get into and will probably be powerful enough. Some extra programming 'oomph' is going to be put in to get into lower languages for better performance.
If you're going for the phone you have to think about what kind of phone.
If you want the application to be accessed through the web, then well, there's your answer :).
For the Windows Phone 7 you can use C# with Silverlight and/or XNA to create your translation application.
So, with C# you can create a C# desktop app and port a -lite version to the Windows Phone 7 with little hassle ;).
When using a statistical method, you also need training data. One good source is the EuroParl corpus, which is based on translations of texts of the European parliament:
The programming language is not really important. Use whatever makes it the easiest to use one of the existing toolkits.
Note that this is a very active field of research in natural language processing, and open domain machine translation is hard to do correctly. Also, the more data, the merrier. Syntax-based systems also require a parser in the pipeline (and good-quality syntactic annotations for the training data).
Since (please do not feel offended) your question seems a bit naïve, let me advise you to do two things if possible: 1. follow a course in machine learning, 2. follow a course in natural language processing, covering at least parsing and MT.
That is a massive project. Have you looked at Google Translate? Hundreds of computer scientists have worked on it for decades and it still is not very good. But if you are motivated ....
My personal preference would be to use Python (it's available on Windows, Mac and Linux). There is a very nice natural language toolkit available for Python which will help you with parsing the input language. During the early stages you want to experiment with algorithms more than being worried about speed, optimization can come later.
A large proportion of the academic Natural Language Processing / Computational Linguistics community use Python, so it really is the natural choice for a project in those fields.
As for how long it will take? You can have something capable of translating a couple of hundred words up and running in hours. To do it properly (at a quality approaching that of even a bad human translator) will take a lifetime.
With the answer to these questions you should be able to easily find out for yourself what language to use, as it seems you have no preference. How fast you want the translations to happen matters because it will tell you how low level of a language you're going to want.
If you're doing it on the web I would give PHP a shot as your main weapon, with the regular open web technologies for client side (JavaScript, HTML, CSS... just building the page).
If you're going for a Windows desktop application, I would use C# because I consider it relatively easy to get into and will probably be powerful enough. Some extra programming 'oomph' is going to be put in to get into lower languages for better performance.
If you're going for the phone you have to think about what kind of phone. If you want the application to be accessed through the web, then well, there's your answer :). For the Windows Phone 7 you can use C# with Silverlight and/or XNA to create your translation application.
So, with C# you can create a C# desktop app and port a -lite version to the Windows Phone 7 with little hassle ;).