the language proficiency of immigrants by exploiting the fact that the initial placement of guest-workers after WWII was … several data sets, we find a small but robust and significant negative effect of ethnic concentration on immigrants' language … presence of the effect. Immigrants with high learning costs are inclined to move to ethnic enclaves, so that the share of …

of immigrants from Norway, Poland, Turkey, and Iran is brought forth. The comparative approach shows that immigrants in …