Who Can Tell The Difference? Goblin, Kobolds, and Orcs

Illustration Source (butterfrog)
Goblins, kobolds, and orcs. Over the years, I have created my own spin on these guys and have found it particularly useful in dungeon settings. I have found that players have been able to differentiate these races in play, so that goblins are not just weaker orcs and kobolds weaker goblins (from a player perspective).
  • Goblins: Goblins are the economic driving force in the upper reaches of world below. They are a combination of organized crime mob and used car salesmen. They move goods and services between the surface world and the world below via trading partners and caravans. Whatever you may need, they "know a guy." They will fight if they have to, but they prefer to wheel and deal and hire gnolls and other tough guys as their muscle. Player characters find they have to come to some sort of "arrangement" with goblins in order to remain in the dungeon, but there are benefits, such as the ability to buy provisions and information (for a price, of course). I have swiped some good gobliny stuff from James Mishler's Monstrous Menaces #2.
  • Kobolds: As the weakest of these three groups, kobolds have been forced to develop some badass attitude and serious survival skills. Kobolds rely on stealth, missile weapons, traps, ambushes, and tactical sophistication to protect themselves. Woe to any player character who is careless in scouting or unprepared to use missile weapons. Player characters have learned to fear the kobold. Kobolds do not surrender and they have no mercy on opponents surrendering to them.
  • Orcs: Orcs are my biker gangs and the bullies of the upper levels of the dungeon and wilderness areas. They love to beat up goblins for their lunch money whenever they can. There are just as prone to fight one another and inter-tribal warfare among orcs is a common occurrence. Orcs are very religious and differences in religious opinions often start and fuel their tribal conflicts. As they are not very bright, these religious battles are more about ignorance of their own religion as opposed to actual doctrinal differences. Orcs are simple-minded bullies and, as a general rule, they will charge into battle against any foe or prey that appears weaker than themselves. Like many bullies, orcs will typically flee or surrender, once it is apparent that they are losing. They are excessively cruel to their own captives, however, so it is a rare orc that will surrender to an orc from another tribe.
How do you differentiate between various humanoid races when you are gaming?