In that period , in the Call for Subscriptions to the Croatian Grammar ( 8 December , 1851 ) he stated his opposition to the Vienna Language Agreement of 1850 and the linguistic concept of Vuk StefanoviÄ KaradÅ 3\/4 iÄ . In that period , in the Call for Subscriptions to the Croatian Grammar ( 8 December 1851 ) he stated his opposition to the Vienna Language Agreement of 1850 and the linguistic concept of Vuk StefanoviÄ KaradÅ 3\/4 iÄ .