One of the tasks of this text is to find out whether the verb chybovat is only imperfective, or biaspectual (imperfective and perfective), while it has never been determined as biaspectual. With the help of introspection, questionnaire and corpus investigation, the author concludes that this verb is ambivalent as to expressing perfectivity. It is just somewhere on the way between the verbs only imperfective and verbs biaspectual, being exposed to many factors determining its further direction. The units that are currently undergoing change should be given, according to the author, increased research attention, as this could lead to a deeper understanding of the principles of linguistic changes. A part of the text is also a reflection on the causes of difficulties in trying to include a particular unit in the corresponding language class.