I have been reading the Great American Essays 2015 to improve my comprehension skills. The essays I have come across use lines that are too abstract in nature and are hard to understand. For example, there's an essay named **This Old Man**,second one in the list. It has set of lines which say:

"My conversation may be full of
holes and pauses, but I’ve learned to dispatch a private Apache scout ahead into
the next sentence, the one coming up, to see if there are any vacant names or
verbs in the landscape up there. If he sends back a warning, I’ll pause
meaningfully, duh, until something else comes to mind"

* What does it mean to send a scout for vacant names?? or What kind of warning does the author gets??

* It's seems very convoluted for me. What does the author trying to convey.

* The fact which I'm worried is, I'm preparing to take up GRE in the month of august and it's reading comprehension section has essays containing similar toned lines.

* If anyone knows anything about that line, please let me know what does it mean. I'm open to take suggestions to improve my passage reading.