Picking a programming language

You can't pick a language to develop a project in, if you don't know:

• anything about the languages you are picking from.
• the pros and cons of using each of those languages.
• what will be required of the project.
• the libraries/resources you will be required to interface with.
• how the languages relate to other languages that are known by the developers of the project. (If any of  the languages will be new.)