As Norwegian society becomes increasingly multicultural and linguistically diverse and prison services continue to see larger numbers of immigrants, our knowledge about the interplay between communication and language and behavioural problems needs to be improved and addressed. The study focuses on language and communication problems associated with misconduct behaviour among immigrant and Norwegian prisoners. A cross-sectional study of immigrant and Norwegian inmates took part in six prisons in Norway, with a total of 250 inmates, where 88(35%) were immigrants and 162(65%) were Norwegian. There was a statistically significant difference between the two groups: manslaughter/murder (p 0.045) and assault/robbery (p 0.008) and crime against property (p 0.004). Norwegian inmates presented three times more risk of misconduct behaviour than immigrant inmates. Those who had communication problems less then once a month presented higher risk of misconduct behaviour than those who had communication problems more often. Those who have communication problems quite often seem to adapt to the situation: they adjust to it and are, in a way, able to put up with the situation. Those who have communication problems more rarely, on the other hand, seem to react with more built-up internal anger and, consequently, with more severe aggression.