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In modern Polish, Ł is normally pronounced /w/ (exactly as w in English as a consonant, as in were, will, wall but not as in new or straw). This pronunciation first appeared among Polish lower classes in the 16th century. It was considered an uncultured accent by the upper classes (who pronounced Ł almost exactly as: л in East Slavic languages or L in English pull) until the mid-20th century when this distinction gradually began to fade.
The shift from [ɫ] to [w] in Polish has affected all instances of dark L, even word-initially or intervocalically, e.g. ładny (“pretty, nice”) is pronounced [ˈwadnɨ], słowo (“word”) is [ˈswɔvɔ], and ciało (“body”) is [ˈtɕawɔ]. Ł often alternates with clear L, such as the plural forms of adjectives and verbs in the past tense that are associated with masculine personal nouns, e.g. mały → mali ([ˈmawɨ] → [ˈmali]).
Polish final Ł also often corresponds to Ukrainian word-final <В> (Cyrillic) and Belarusian <Ў> (Cyrillic). Thus, “he gave” is “dał” in Polish, “дав” in Ukrainian, “даў” in Belarusian (all pronounced [daw]), but “дал” [daɫ] in Russian. The old pronunciation [ɫ] of Ł is still fully understandable but is considered theatrical in most regions.