On two types of natural languages - Some consequences for linguistics

First of all, this paper attempts to introduce and define the difference be tween first order and second order natural languages based on the differenc e of being subject to L1 acquisition or not. Secondly, I will try to show s ome consequences resulting from this distinction w.r.t. language change (na tural vs. semi-natural LC) and thirdly, following from this, for linguistic research in general. The results may be of relevance for linguistic theory (and methodology) as well as for a theory of LC (allowing, e.g., to draw t he borderline between tee (bio)linguistic and social domains of languages m ore accurately.) Finally, I will try to show how one could figure out const ructions resulting from semi-natural LC (via diachronic, comparative and di alectological comparisons).