Interesting thread in a number of ways.... just, for the record....
Tomoe nage is probably best described as a "pendulum", or "droplet" throw... a tomoe is a swirling form, think of one half of the classic "Yin'Yang" symbol. The tomoe is found in a number of forms in Japanese culture, such as in groups of three (mitsu-tomoe) in a number of Japanese family crests as an example. "Kaiten nage" would be a "rotating", or "rolling" throw... a "stomach throw" would be "hara-nage".... a "circle throw" would be any of a number of terms, "en no nage" would be the most literal, although it could be "Enkei nage" (circular shape throw), "Marunage" (round throw), or a couple of others... but most commonly, the term "en" would be involved. And, while I'm here, from about page three, Blackknight mentioned that "Ken" means "punch"... actually, it means "fist", or "weapon", implying the object used to strike or attack... the most common term for a punch is "tsuki", more literally meaning "thrust (with a weapon, in context)"... classically, the idea or concept of punching in Japanese arts simply isn't the same as in Western ideals and cultural understanding.
And that brings us to the thrust of the question... why use Japanese terminology all the time? Well, for one thing, I'd disagree with the premise that practitioners of Japanese arts think of Japanese as a universal language of all martial arts... however, we do tend to think of the Japanese terms as universal, or at least, intrinsic enough to the arts we study to validate using them for preference over less specific terms (from inaccurate, or more vague attempted translations)... a good example of which is the discussion of the above tomoe nage. A number of "translations" were given, none of which were actually accurate, but were attempts to describe the throw in English. Despite the variation in English descriptive terms, using the term "Tomoe nage" is universal enough (largely thanks to the usage within Kodokan Judo... we'll come back to that) that, regardless of the specific English characterisation, everyone knew the throw being meant. In fact, reading "the throw Captain Kirk used so often" meant nothing to me... but the term "tomoe nage" instantly told me what Gerry was talking about.
By the same token, I have an immediate understanding of what an Ippon Seoi Nage is, regardless of how it is described in English (a "shoulder" throw... it's not, for the record... "one arm shoulder throw", which could be any of a number of variants I know that can be commonly called that... a "one arm throw", which again could apply to a number of actions... and so on). And again, just for the record, Seoi Nage is one of those things that has a common English description that is sometimes taken to be a translation, when it's not... it's commonly referred to in English as a "shoulder throw", however the term for "shoulder" (that would be a kata-nage, for the record) does not appear in the name at all... in fact, when you look at the name in Japanese, it is comprised of the characters "Sei" č, meaning "back", as in your spine/shoulder blade side of your body, "O(i)" č² ć, meaning "to bear (upon)", and "Nage" ęć, which means "to throw"... giving an actual translation as "to throw by bearing the opponent upon your back", a fairly accurate description of the category of throws... but not what you find in the English terms.
So why do we insist on using these Japanese terms? Often because they give information that is lacking in the English descriptions... it can be technical (as in Seoi Nage), cultural (such as the imagery in Tomoe Nage), historical, tactical (particularly within the older, classical arts), and more. It's less about the terms being universal, even within Japanese arts, as many different arts will use different terms for the same, or similar concepts... or use the same name for different ones. As an example, many are familiar with the term "Bo" meaning "staff"... or "Jo" meaning "stick"... and many have an idea of what those weapons are. However things are not quite that simple... for example, the "Bo" might be a Rokushaku-bo (almost exactly "six foot staff")... or it might be given a name such as Chobo (elongated stick), as used in schools such as Yagyu Shingan Ryu Heiho... or Nagabo (long staff)... or the length might be longer or shorter than what is expected (YSgR's Chobo, for instance, is closer to 5 feet, other schools use slightly longer staves for reach advantages, and so on). A "Jo" is commonly thought of as a four foot stick weapon, primarily from Shinto Muso Ryu, and also seen in many forms of Aikido... and is, like the Bo, sometimes called a Yonshaku-jo (four foot stick)... except Muhi Muteki Ryu refer to their staff weapon as a Jo, despite being close to 6 feet long... and the idea of a Jo's length, even in schools such as Shinto Muso Ryu, has varied over the years. Then we have other forms of Bo or Jo... such as Hanbo... Tanbo.... Tanjo... Te Giri Bo.... and many others that might or might not be recognisable... and might be used interchangeably, or might be very specific... and even that varies with the exact same terms. A classic example is the short sword... it might be called a Shoto, or a Wakizashi, or a Kodachi... and each might be used to describe the exact same thing... or might mean something specific, such as a specific weapon or part of a school's syllabus... and the one teacher might use the same term as either generic or specific... Japanese is all in the context. So don't worry, even Japanese martial artists get a bit confused by the Japanese terms!
But why is it so important to use the Japanese terms? For that, we need to do a little historical study... starting in the Japanese school system with Kano Jigoro, founder of Judo, and his Kodokan training methodology...
In the late 1800's, a young martial artist called Kano Jigoro, who had studied and become licenced in two distinct classical Jujutsu systems, Tenjin Shin'yo Ryu (a relatively "new" classical art, being in it's second generation when Kano studied it, having been formed at the very end of the samurai rule), and Kito Ryu (an older art that included a number of facets of education, such as fighting in armour). Kano took his studies in these arts, as well as his knowledge of a few others and his understanding of academic education methods, and began to formulate a new training methodology, which he would come to refer to as Judo, distinct from the older Jujutsu systems. He altered a number of technical aspects, as well as developing a new teaching approach, focused more on developing skills in a confined area, rather than the more tactical centric approach of the older arts. This came to be symbolised by the free-form training and competitive formats that Judo is known for (for the record, many older Jujutsu, and even weaponry arts had extensive free-form training methods and sparring-like approaches), to the point that Judo became, in it's early days, a way for classical practitioners to test their abilities within Judo's context. It would not be uncommon to see a practitioners name card as stating, for example, "Takenouchi Ryu Jujutsu, Chuden Menkyo (Middle Licence) - Kodokan 4th Dan", indicating that the person held a middle level licence in Takenouchi Ryu, a classical jujutsu and weapons art, and had tested their skills to the level of 4th Dan in the open training at the Kodokan or one of it's affiliates. Due to this cross over between schools, general terminology came to be recognised throughout various arts, becoming a sort of universal terminology within Japan itself. This was the beginning of the development of standardised terminology for Japanese arts.
The next big development was found in the Japanese government. After the end of the Tokugawa Shogunate, and the development of the Meiji Restoration, where the Emperor Meiji, thorough his supporters, was restored as the ruler of Japan, and the Shogunate (military rulership) was overthrown, a number of edicts were passed that essentially ended the samurai, and the caste system that had ruled Japan for centuries. Having endured under the rule of the samurai for so long, much of Japan was not keen on embracing the culture that had acted as oppressive overlords for so long, leading to a great push back against anything seen as representing Japan's past. The newly formed government, however, as well as many business concerns, being headed by former samurai or samurai families, wanted to assist in preserving the culture of their ancestors, so a number of bodies were formed for the promotion and preservation of Japanese martial arts, under the guise of preserving unique Japanese culture. These bodies were responsible for things such as standardising modern martial arts, such as Kendo, Iaido, and so on, as well as being instrumental in helping rebuild the arts after the ban following WWII. They formulated the 9 Budo (Martial Ways/Arts) of Japan, giving particular status to nine "modern" budo arts as representative of Japanese culture; Kendo (modern sword art, which also acts as an umbrella for Iaido [sword drawing], and jodo [short staff]), Kyudo (archery), Judo (a throwing based competitive art), Aikido (a modern art based in locks, throws, and pinning methods), Karate-do (specifically referring to Japanese-based groups, such as Shotokan, Kyokushin, Wado-ryu etc, rather than the Okinawan forms, such as Uechi Ryu, Goju Ryu etc), Sumo (a very old form of grappling competition), Shorinji Kempo (ostensibly a mix of native Japanese arts and Shaolin-based kung fu... Shorinji Kempo is pretty much the Japanese pronunciation of "Shaolin Chuan-fa/Fist Methods"), Atarashii Naginata ("new" naginata, a long pole arm with a curved blade), and Jukendo (bayonet fighting based on older spear methods, and developed in the early 20th Century).
The Nippon Budokan organisation developed a "Budo Charter" for the promotion of Japanese Culture through Martial Arts, and began to push these ideas with sponsored visits, lectures, demonstrations, and more throughout Japan and the world. This, of course, has lead to a strong connection between the concept of teaching Japanese martial arts, and the teaching (and promotion) of Japanese culture... which is expressed not only through the actions, but through the language, which, of course, gives a greater appreciation back to the source of the art itself... Japan.
From this, we can see the usage of Japanese terms is three-fold (at least):
- Ease of communication by using terms that are understood by all involved (in the relevant arts)
- Lack of confusion by using many (often inaccurate) non-Japanese terms.
- Promotion of Japanese culture through martial arts.
Of course, each culture and community has it's own language... and the terms are found in each cultures art... to a greater or lesser degree. BJJ uses a mix of terms from different cultures, including Japanese (Kimono, Jiu-jitsu, etc), English (Mount, Guard etc), and Portuguese (Omoplata, Americana, and so on), reflecting it's mix of heritage and position in the world today... Chinese arts use Mandarin or Cantonese, depending on their origins... Korean arts often use Korean, especially in Korea (obviously!)... but Japanese arts tend to focus more on the idea of promoting Japanese culture, giving rise to the seemingly (but, I feel, not substantially) higher degree of usage of Japanese terminology. However I do feel that it is mainly used to speak within the context of Japanese arts, rather than being seen as "standard language" for all martial arts.
