You cannot just simply convert .wav audio files to a text file some universal converter. You will need a dedicated transcription software (like VoiceBase) that can capture the speech from an audio file and save the words as texts. The result is usually not perfect and needs some manual editing afterwards.
Convert WAVe PCM Sound, standard Windows sound format to Text file.
We have found one software suitable in our database for this conversion.
On-line services software - convert wav to text on web
A Voice Search & Transcription Platform
Convert from wav file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.