This PhD dissertation is a linguistic ethnography of a metal foundry in the Dutch province of Limburg, in the Dutch-German borderland. When its fieldwork data were collected in 2017, over 300 people with many different language backgrounds worked in the production departments of the foundry, including Dutch, German, Limburgish, and Polish, as well as Arabic, Greek, Russian, and Turkish, among others. Some workers lived on the Dutch, others on the German side of the border. Slightly more than half were temporary workers, and an important part of their daily and nightly work consisted of interactions with machines. The dissertation contains lively and detailed descriptions of life in the metal foundry. A returning issue is to what degree the language diversity in the workplace constituted a ‘problem’ or not, and if yes: what the nature of this ‘problem’ was. The dissertation shows that speakers of majoritised languages in the foundry often found the language diversity more problematic than speakers of minoritised languages, that the often-temporary work relations constituted a bigger obstacle for communication and workplace learning than language diversity in and of itself, and that production workers often had more problems understanding machines in the workplace than each other. The dissertation reflects upon these and other observations and applies both established, linguistic-ethnographic as well as post-humanist concepts.