The present paper only deals with the Slavic languages that are in use in present-day Poland. There is no arguing that the populations living in the north-east part of Poland (the region of Bialystok) are Belarusians and so they speak the Belarusian language, or that south of this region, along the Polish-Belarusian and Polish-Ukrainian borderline there are villages where people speak (or have been speaking not long before) Ukrainian dialects. South-east of Poland (The Bieszczady Mountains) had been inhabited by the Lemkos until 1949, when they were deported westwards. Linguists classify their speech as belonging to Ukrainian dialects. The Lemkos are divided in their opinion on that matter. Some say they feel to be Ukrainians, and they consider their language a Ukrainian dialect. Others are not ready to recognize their Ukrainian identity, and claim their language has an independent status. Both the Belarusians, Ukrainians and the Lemkos (as well as a small number of non-Slavic Lithuanians in the very north of Poland) live within the Polish language environment, which makes them bilingual.In the remaining part of the country there lives a population speaking a variety of dialects within the Polish language. It is for at least a century that the contentions about the language status of Kashubian has been going on. Kashubian is the speech of the ethnic groups living south of Gdansk. They inhabit the area of about 6 thousand square kilometers. The latest reports show that the Kashubian population equals about 300 thousand. Traditionally, in Poland the speech of the Kashubians is regarded as a dialect of Polish. Various researchers from beyond Poland, and some younger Polish linguists refer to it as the Kashubian language. Lately, a lot has also been said on the growing language separatism between the Silesians.The borderline between what we are ready to name a language or a dialect is unclear, and it seems one has to agree with H. Popowska-Taborska (1998: 87) in saying that the judgement depends on the criteria one prefers. Dixon's (1988: 7) distinction between the political and the linguistic understanding of what is a language, and his proposal to consider those varieties of language—in the linguistic sense of the term—which are mutually comprehendible to be dialects is impressive as regards its simplicity. Unfortunately, in practice it leaves a number of problems unresolved. This paper analyses the linguistic status of the Slavic languages and dialects used within the territory of present-day Poland, drawing upon both linguistic and sociological data.