Language learning

..learning a language is seen as language development [in complex systems theory] rather than as acquisition. In other words, language is a process of dynamic adaptation (Larsen-Freeman and Cameron 2008: 157) rather than something that, once learned, is “possessed” for all time. From a complexity point of view, language can never be in an entirely stable state, so it cannot be “acquired” once and for all."—J. Naude in  Diachrony in Biblical Hebrew, page 64

<idle musing>
Indeed. I hadn't thought of it that way before, but it's true even of English. Every day I'm learning a new nuance to a word or an entirely new word. If that is true of English, how much truer it is of a second/acquired language!
</idle musing>