The present invention provides a method of generating text transformation rules for speech to text transcription systems. The text transformation rules are generated by means of comparing an erroneous text generated by a speech to text transcription system with a correct reference text. Comparison of erroneous and reference text allows to derive a set of text transformation rules that are evaluated by means of a strict application to the training text and successive comparison with the reference text. Evaluation of text transformation rules provides a sufficient approach to determine which of the automatically generated text transformation rules provide an enhancement or degradation of the erroneous text. In this way only those text transformation rules of the set of text transformation rules are selected that guarantee an enhancement of the erroneous text. In this way systematic errors of an automatic speech recognition or natural language process system can be effectively compensated.