system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: in the military, what are NCO's, how do they differ from normal officers, and why do some countries not have many of them?

What does non-commissioned mean? Do these officers go through officer academy like ordinary officers? And why do some analysts say that having a strong NCO class is essential to a well-functioning army (i.e. what can they do that a normal officer can't?)

Thanks in advance!
gpt
In general, an officer is a soldier who has authority over other soldiers. In modern militaries, a commissioned officer is an officer who is formally granted that authority by a government.
This document granting such authority is called a commission, as in the officer is literally commissioned by the government to lead. A non commissioned officer is an officer who was not expressly commissioned, but has been promoted to the office.

What this means is that commissioned officers are, usually, trained at an academy, commissioned, then assigned a duty. These officers are generally trained for leadership or specific roles *before* they do them. Non commissioned officers enlist, are assigned a duty, then promoted to leadership as they prove competency/gain seniority.

Commissioned officers are the "educated" academy folks, the ones who are trained to lead, command, or perform specialized jobs such as fly a fighter plane, or command a platoon of tanks. Non commissioned officers are from the common soldiers, the enlisted troops. They start at the bottom, they do the "grunt work," are the ones "on the ground," and make up the bulk of the military.

This is with regards to a modern national military. Older militaries were very different in not just organization, but in their function and purpose.

While not part of the original question, anyone interested should read the other posts regarding warrant officers, another important part of military leadership.