The paper reports on some special problems arising during the building of a bilingual dialogue system, concerning especially parsing and dialogue modeling. We describe an unique automated formalization technique, with help of which authentic dialogues recorded in city information centres can be transformed into a special internal representation, closed to the symbolism of pseudo-flowcharts. The dialogue representation consists of many simple dialogue steps, each of them represents a~very small part of the dialogue being described by 2 - 3 sentences. The use of the developed technique requires the preassignment of dialogue acts to the corresponding problem domain, preselection of typical user utterances and their careful transcription into grammatically correct defined sentences, machine comparison of transcribed user's utterances with preselected domain oriented sentences and recognition of the concrete dialogue step. The developed formalization technique enables the generation of an effective 
dialogue management, further implemented in a standard city information system communicating with the user in two different languages - in this case in Czech and German ones. The second prestigious advantage of the presented technique is the possibility of an automatic generation of the grammar, formally describing the subset of utterances (sentences) from the given domain; the grammar is later used in the step of linguistic analysis of user utterances.