Install espeak-ng if it's not installed already.

src/synthesize.py

@@ -73,7 +73,7 @@ def synth_espeakng(text:str, model:str):
         Streaming Wav and sampling rate.
     '''
     if model is not None:
-        subprocess.run("sudo apt-get install espeak-ng") # Make sure espeak is installed -- not the most elegant solution, can swap for python API when that is resolved
+        subprocess.run(["sudo apt-get install espeak-ng"]) # Make sure espeak is installed -- not the most elegant solution, can swap for python API when that is resolved
         subprocess.run(['espeak-ng', f'-v{model}', "-w test.wav", text]) #.returncode
     
         sampling_rate, wav = wavfile.read('test.wav')