Reidar Astås’s scientific contributions

... Increasing contact with Central Europe in general facilitated the spread of linguistic innovations into North Germanic, although it is not always possible to reconstruct exactly which languages were involved and how. The effects are most obvious in the lexicon, where-as in other Germanic languages-many Greek and Latin loanwords were borrowed early on, usually via West Germanic or Romance (Astås, 2002;Helander, 2005). More notably, however, work in areal typology has shown that important grammatical innovations up to the Middle Ages have to be considered as contact-related rather than purely internal developments, resulting in structural convergence of North Germanic toward what has sometimes (and controversially) been labeled Standard Average European (Haspelmath, 2001). ...

Reference:

The Impact of Language Contact on North Germanic