[BUG] Text-to-speech only works for single words

[nmehlei]

Describe the bug
Text-to-speech seems to work fine (in my case via MQTT) with something like {"speak":"Hello"}, but as soon as there are multiple words involved, e.g. {"speak":"Hello Dave"}, there is just no output anymore. As this is not documented like that I would assume this is not by design (and would be a very unfortunate limitation anyway).

To Reproduce
Steps to reproduce the behavior:

• Try to use the speak command via MQTT with multiple words, e.g. {"speak":"Hello Dave"}

Smartphone (please complete the following information):

• Device: Fire HD 10 Plus (11th Generation)
• OS: Fire OS 7.3.2.2
• Application version: v0.9.6 build 0