The consensus among linguists is that modern, standard Czech originated during <answer>the eighteenth century</answer>. By then the language had developed a literary tradition, and since then it has changed little; journals from that period have no substantial differences from modern standard Czech, and contemporary Czechs can understand them with little difficulty. Changes include the morphological shift of í to ej and é to í (although é survives for some uses) and the merging of í and the former ejí. Sometime before <answer>the eighteenth century</answer>, the Czech language abandoned a distinction between phonemic /l/ and /ʎ/ which survives in Slovak.
When do linguists agree modern Czech originated?
the eighteenth century