The use of titles in the martial arts is as common place today as leaves on trees. There never has been a standard for the most part, especially as so many occidentals or non-Asians have risen up in the ranking systems.
Starting at the color belt levels (Kyu 級 Japanese) (Keup 급 Korean) is one of the most common and easiest to understand. They are the students below black belt and so not to much to say, in regards too titles. There is a variety of colors from white to brown and colors like camouflage and purple, red, orange, yellow blue are used nearly universally. Most systems recognize a 10 to 1 or a 9 to 1 Keup/Kyu system. With the highest numbers being the lowest, and then working down to the higher (lower numbers).
Many organizations or systems may start to call the 2nd & 1st Keup/Kyu’s as “senior students” but other then that, the color belt systems and titles are pretty simple.
The real confusion starts at the black belt levels! Belt belt ranks (and color belts as well) are just a little over a hundred years. They started in the Meiji period of Japanese reformation and has grown a lot since. The original color belt and black belt colors were simply white, brown and then black.
The Dan 段 (black belt) system came in to the martial art world around 1883 by the founder of Judo 柔道 Kano Jigoro 嘉納 治五郎. The Dan levels had actually been in use for many years before Kano used them in his Judo. They were first used in the Asian game of Go by the mid 1600’s and and the Dan rankings were likely based on early forms and systems including Chinese Go ranking systems dating back to the early 3rd Century, and possibly even on the Royal Chinese Court itself.
The Dan ranks go from 1st up to 9th (or 10th)
With the brief history of the ranking system out of the way, one of the first things we learn in any martial art us how to address the instructor(s). Now, how we learn in schools (North America, Europe etc) is the proper way to address your teachers is by saying “Mr./Mrs/Miss/Ms. Johnson” when asked a question we would simple say “yes Ms. Johnson.”
One major Taekwondo organization (Mid West Karate Association AKA American Taekwondo Association® now Always Taking Action™ in the 1960’s used this principle. Using the instructor title as “Mr/Mrs. Etc.” And this system (at least in the USA) worked well, until about the mid 1980’s. What changed was a couple of things, number one being there were now more occidentals gaining rank and there was more exchange of information and materials from Asia (Japan and Korea especially) and so more and more 2nd generation black belts (2nd generation black belts in the notion of not from Asia).
Ed Parker who was the head/creator of American Kenpo Karate used titles for his black belts and he based them off of the Western use of academic titles. For his beginner belts (color belts) he used titles that many other systems do, such as Beginner (white & Yellow), Intermediate (Orange & Purple), Skilled (Blue & Green), Advanced or Semi Skilled (Brown), and then for his black belts he gave each one a classification.
In American Kenpo the 1st Degree is a Junior Instructor, 2nd Degree is an Associate Instructor, 3rd Degree is a Head Instructor, 4th Degree a Senior Instructor, 5th Degree a Associate Professor, 6th Degree a Professor, 7th Degree a Senior Professor, 8th Degree Associate Master, 9th Degree Master and 10th Degree Senior Master of the Arts/Grandmaster.