Some time ago my partner Pedro Santamaría published this entry, in which he told a trick to be able to choose the language of an application before launching it . MacUpdate
I’m clarifying this just in case someone wants to look for three feet on the cat.
Today I discovered a much more comfortable, quicker and easier way. Language Switcher is an application that allows us to start any application we have installed in the languages in which it is available. From the Language Switcher itself it will allow us to choose one of the languages and run the application . If the application is not in the application folder, we can choose it via File, Add in the menu . In addition, we can tell Language Switcher to always run the application in the chosen language.
Another interesting option is that it allows you to start several applications at once.
Language Switcher is free (the author accepts donations) and is optimized for Snow Leopard .