The article investigates the linkages between urban transformation and informal verbalizations of everyday spaces among male juveniles from Sörnäinen (a working-class district in Helsinki) in 1900-39. Sörkka lads' biographically and contextually varying uses of slang names mirrored their itineraries across the city in the search of earning and spare-time opportunities. As a simultaneously practical and stylistic street language, the uses of slang both eroded (in uniting bilingual male juvenile groups) and strengthened (as with providers and teachers, workingclass girls, upper-class urbanites and rural newcomers) existing socio-spatial boundaries. Unlike in the late nineteenth century Stockholmska slang studied by Pred, openly irreverent toponymic expressions vis-à-vis the hegemonic conceptions of urban space were relatively few in early Helsinki slang. 2 E.g. D. Garrioch, 'House names, shop signs and social organization in Western European cities', Urban History, 21 (1994), 20-48; M. Azaryahu, 'The power of commemorative street names', Environment and Throughout the article, we utilize the following etymological key to indicate which language(s) each slang toponym mentioned apparently stemmed from, as well as a decade of its first known usage: S = Swedish, F = Finnish, R = Russian, E = English, O = other language; 1800 = prior to twentieth century, 00 = 1900s, 10 = 1910s, 20 = 1920s, 30 = 1930s. Aström, Samhällsplanering och Regionsbildning i Kejsartidens Helsingfors (Helsingfors, 1957), 42-316; Waris, Työläisyhteiskunnan, 13-29, 108-22.