This paper highlights a previously unnoted timing discrepancy in the first-language (L1) acquisition of geen (‘no’) in Afrikaans and Dutch. Building on White, Southwood & Huddlestone (2022) and van der Wal (1996), we report on a comparative Afrikaans-Dutch corpus study focusing on child(-directed) language that suggests that Afrikaans geen is acquired significantly later than Dutch geen. At the same time, it also highlights a striking difference in the use of NEGATOR+INDEFINITE ARTICLE-containing structures in the two languages. To further probe this discrepancy, we conducted an exploratory investigation of two suitable corpora of adult Dutch and Afrikaans. This reveals various collocational shifts and a reverse in the default negation pattern with indefinite count nouns: where Dutch employs geen, Afrikaans uses nie 'n (‘not a’). Considering the importance of object-denoting count nouns in early L1 acquisition, this would be expected to affect the timing of the acquisition of geen. The paper concludes with a discussion considering the likely origins of the shift in default pattern. The innovation of the moenie-imperative is argued to be key, given the acquisitional significance of imperatives and the fact that somewhat similar changes are attested in the history of English, which also innovated a prohibitive-marked negative imperative.