The transferability in OOP and software design tends to stem from knowing the advantages and disadvantages of the various design patterns that occur over and over and over again.

Singletons, publish/subscribe, facades, adaptors, abstractions... all can be implemented in almost any language that supports OOP principles.

Further, being able to "think" in objects and knowing when and when not to use inheritance, structuring and composing object dependencies, isa/hasa relationships... again, transportable and transferable knowledge.