This study reports on the linguistic behaviour of 39 university students from Moravia (in the east of the Czech Republic) living at a hall of residence in Prague, Bohemia (an area covering the west/central parts of the Czech Republic). In Bohemia, Moravian dialects and Standard Czech (SC)--an archaic and semi-artificial standard dialect that is rarely used in informal communication--are both stigmatised, although for different reasons. It has been speculated therefore that speakers of Moravian dialects living in Bohemia quickly start to drop or avoid marked items of their localised vernaculars and accommodate to Common Czech (CC), a non-standard koine spoken throughout Bohemia and the westernmost parts of Moravia. To date, however, this hypothesis, which was formulated by linguists who advocate CC as a second central variety of Czech, has not been substantiated by empirical evidence. This study is the first attempt to systematically describe the accommodation of Moravian migrants in Bohemia. The results are based on the linguistic behaviour of a representative sample of informants stratified according to four independent social variables; informants' accommodation is quantified according to their acquisition of six CC variants. The aim of this paper is to describe the types of accommodation that are observed in first-generation dialect contact. I consider which features of the host variety are acquired the most or least (and why), how quickly individual features are assimilated and whether accommodation follows a specific route. Emphasis is placed both on the language-internal and in particular on the extralinguistic factors that promote/accelerate, or delay or even prevent the assimilation of particular linguistic items. I highlight several types of partial (incomplete) accommodation, including forms that are intermediate between those found in the migrant and host dialect ("interdialect" forms) and "hyperdialectisms", which are the result of migrants' misanalysis/overgeneralisation of the host variety. This study provides valuable data on the processes involved in the accommodation of first-generation adult migrants, which we can test against the frameworks that have been advanced--on the basis of just a few empirical studies--in an attempt to explain the character of and variation in long-term accommodation, and which we can compare with results elicited in other studies of dialect contact in societies with a different sociolinguistic profile.