Poor naming for functions taking or producing strings.

[guygastineau]

I started out just following the naming conventions from the festival library itself. They use the word text where I have chosen to use the datatype String. This could result in confusion in the haskell ecosystem, since text usually refers to the datatype Text and the package whence it hails.

[guygastineau]

I think sayText should just be say for example.

This would also open the possibility of a parallel Text based API without confusion, although I don't think it is necessary. Long texts will take a REALLY long time for waveform synthesis and the flow/timing in the speech won't be great, so users are incentivized to break longer text into several small snippets. Therefore, sticking with String is probably fine, but we will still want to change the naming conventions to avoid confusion for library users.