You would use the informal word when you are speaking to someone with whom you are familiar, such as your father or a close friend. The informal would be used if you were speaking to someone that is unfamiliar to you as it does not introduce a familiarity into the conversation that could make things awkward learn french software. Still, if your goal is just to learn a few basic French phrases in order to be able to convey an idea, the general speech pattern would work, regardless of whether you were using an informal or formal phrase. You can learn these phrases easily with the use of an online tutorial or a language CD. It can help you to grasp the basics, learning the complexities of the language will come in time.