There is provided a system and a method for detecting meaningless lexical units in a text message, the method comprising: performing a syntax analysis of the text message and determining at least one lexical unit as a first potential meaningless lexical unit; determining a control sum of the first potential meaningless lexical unit; matching using a first parameter, the first potential meaningless lexical unit with lexical units from a plurality of lexical units from a lexical units database, wherein matching using the first parameter comprises matching a control sum of the first potential meaningless lexical unit with control sums of meaningless lexical units from the lexical units database; determining the first potential meaningless lexical unit is a meaningless lexical unit if the lexical units database includes at least one meaningless lexical unit with a control sum corresponding to the control sum of the first potential meaningless lexical unit.