kata is japanese (i thought anyway)
depends on the style.....there are so many, and some arent so good others are better. some styles are just lots of fancy hand movements etc which isnt especially practical, others focus a lot more on practicality
some styles (like dog style) concentrate on taking the opponent to the floor and beating him there, some are all about quick strikes etc, some are about conditioning your body like crazy....theres so much out there
i do a southern style......in terms of outright practicality (i.e. getting good fast) its not great as their is so much to learn, it depends on if your instructor spoon feeds you or expects you to learn lots yourself. other styles (non kung fu) may be faster to learn & therefore more effective. but (southern) concentrates a lot more on handwork, which i think is better than northern (flowery kicks and shit
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my style has strikes, joint locks, stand up grappling, groundwork.....i do like it a lot. i am quite biased though, ive never really experienced other styles. speaking to people within my club who have done other styles before (tae kwon do, thai boxing, kick boxing etc) they agree it is effective, and have used it succesfully as bouncers in nightclubs etc. they (thai boxers) also on the flip side say thai boxing is more brutally effective on the streets due to the simplicity/ease of learning of it
it really depends on the club i guess. go down and take a look. so much of it has been diluted nowadays that you get guys doing patterns (or karate katas) to music, in dance gear etc, so you got to make sure you get a good one, the most popular ones arent necessarily the best. hope this ridiculously biased kung fu opinion helps