The paper deals with the analysis of J. Palkovic dictionary work from the beginning of the 18th century. Attention is concentrated on the processing of several common expressions existing in the Slovak language and in the Czech language, as well as on lexemes existing only in the Slovak language. Research and comparison of some processed lexemes reveals the fact, that this dictionary reflects the viewpoint on the language adequate for mentioned period of the time. Nevertheless, the Dictionary is evaluated as a suitable handbook for students and for some other Slovak and Moravian social groups from the period, which precedes the period of Ludovit Stur activity. The Dictionary includes an extensive Slovak vocabulary, which made it very popular. J. Palkovic attracted users attention with the topical question connected with the infiltration of the Slovak language into that period of time existing Czech literary language in Slovakia.