We deal with the acquisition of polarity items "i" and "ani" in utterances of Czech children. These items frequently function as conjunctions and particles in Czech language. we treat them as focus/scalar particles. These particles are specific for their sensitivity to probability. The aim was to find out whether children at primary school (junior school age) have already acquired these items and whether they are able to connect them correctly with alternatives on the scale of probability. The research was conducted with children from the second and the fourth grade at primary school.