It has been hypothesized that the Finnish language is well suited to speech-to-text conversion for the communication aids of the hearing impaired. In a related study it was shown that, depending on context, 10 to 20 % of phoneme errors can be tolerated with good comprehension when reading text converted from raw phonemic recognition. Two sets of phoneme recognition experiments were carried out in this study in order to evaluate the performance of existing speech recognition systems in this ap-plication. For telephone bandwidth speech both systems showed speaker dependent error scores of about 10 % or below, thus supporting the feasibility of the application. For speaker independent cases the error rate was typically more than 20 % which is too high for effortless and fluent communication.