With nkululeko since version 0.68.1, you can re-name data fields (columns in your data table) by setting the following in your ini-file:

[DATA]
databases = ['mydata']
mydata.colnames = {'Participant ID':'speaker', 'sex':'gender', 'Age': 'age'}

which means, that, before further processing, the Participant ID field in your database mydata will be treated as speaker label and so on.