The GPL v3 FAQ contains this item and this item that discusses the notion of a larger work and what constitutes a larger work. Our interpretation of GPL v3 is that language packs and, more generally, any code (e.g., modules, themes) that interfaces directly with (and would not work without) Sugar Community Edition form a larger work and are thus subject to GPL v3.
This is contrasted with extensions that interface with Sugar Community Edition via web services APIs (i.e., SOAP APIs). These extensions run independently of Sugar Community Edition and can presumably work in the absence of Sugar Community Edition, do not form a larger work, and can therefore be licensed under a non-GPL license.
Posted in: Sugar CRM