Yes, you can plug an external speaker into the side of the microphone opposite the PTT switch.? It does feel a little awkward having an extra cable attached to the mic.? I suppose one could feed the speaker cable through the center of the coiled mic cable.? But that may present other problems when stretching the coiled mic cord.
Since I have a nice small powered speaker, I plan to take a 7-pin connector that will attach to the REM DATA port, using the audio out pin, and make a special cable with a 3.5mm connector that will plug into the speaker.? Due to a business trip, it will be next weekend before I can try this and report back.