The article focuses on the hypothesis that the structural complexity of languages is variable and historically changeable. By means of a quantitative statistical analysis of naturalistic corpus data, the question is raised as to what role language contact and adult second language acquisition play in the simplification and complexification of language varieties. The results confirm that there is a significant correlation between intensity of contact and linguistic complexity, while at the same time showing that there is a need to consider other social factors, and, in particular, the attitude of a speech community toward linguistic norms. *