OK, the thing to troubleshoot here is the crash, since we already know that if suspend isn’t being successfully called, we’ll see PocketsphinxController try to recognize speech (synthesized or otherwise) that is occurring in the same audio environment in which it is listening. Let’s focus on why calling suspend results in a crash, since that shouldn’t happen.
When you get the crash, while the program is still attached in the debugging console (i.e. you can see the prompt “lldb” in blue), can you type “bt” into that prompt and show the results?