"Neh" comes from ね, and is oft-used by "American otaku" in butchered English like:
"Wow, Jill-chan is so kawaii, neh?"
I'm a bit disappointed to see those horrible habits of speech in aikido groups, too...
"Bisuteki" should be "Bifuteki;" people don't really say "besuboru" here (although I have seen that referenced in English media a few times), they 100% say "yakyu" instead.
English is basically the "new Chinese," and every year they take new loanwords from English, to the point where noone really knows what they are talking about, but they get used to memorizing arbitrary words and acronyms (for which they do not know what they stand for). In the end, there are just a whole bunch of synonyms, which is expected, as the usage of loanwords comes from learning English in school, where teachers and students assume that English vocabulary are exact meaning replicates of native Japanese words (except for foods like butter). Thus, although they have doubled the number of words to choose from in Japanese, they have not gained anything out of it (new ideas), while obfuscating understanding of the language.
If you look at business material, you will see that Japanese language is basically 65% Chinese characters, 30% English loanwords in katakana, and 5% Japanese particles (ga, no, etc.).
Doing the reverse to demonstrate in English, we would say things like:
Aikido is sugoi gendai budo that watashi suki.
Or, more accurately:
Aikido is susumajii ima's yo's mononofu's waza that ware suku.
(In other words, hardly any English remains at all.)
Arigato does not come from obrigato - that is a myth. Arigato is the shortened form (because polite Japanese is so darn long) of "doumo arigatou gozaimasu," which means "how so difficult to have it is."
Dou = how
Mo = also
Arigatougozaimasu = polite way of saying Arigatai
Arigatai = Ari + gatai
Ari = have, exist
-Gatai = difficult
So, arigatou means "hard to have" or "hard to exist," i.e. the idea is that "I am sorry, how can this be, I cannot have this, I cannot accept this" - which is not the same as "thank" per say, but is their own native idea that is close to it.
They HAVE adopted the Chinese "ganxie" as "kansha," which is also a way to "thank" someone; also related, however, is that originally, the Chinese "xie" seemed to be more of an apology than a thank you.
(And then, some people flippantly say "sankusu" (thanks) nowadays here, too - that is from Engrish, of course, minus the "th" sound.)