Writing a text bubble coming from a military headset. How do you do that? Especially, when the headset is not visible or the character wearing the headset is small. I am not sure how comics handle that. Assume that the character speaking to the character wearing the headset is far away and not inside the comics panel.
This would really be up to artist preference, but there are plenty of options. Personally I would make the bubbles square instead of round, maybe jagged in shape to give the impression of static over the radio. Often times there won't even be a 'tail' on the bubbles if the character speaking isn't visible in frame either. You could use color coding to help indicate the difference between thoughts and spoken words. I attached a little snippet I made super fast with just what Microsoft Excel comes preloaded with: