Despite losing the ability to speak most of these languages I have learned, I have not forgotten the grammars of each... and because of my maths interest and our natural ability to pick out patterns, I tend to spot and remember the patterns. I think it'll help should I ever need to recall the languages I have learned. The vocabularies should slot back in place after a few weeks...
After University I studied Spanish, Cambodian, Indonesian... some Tibetan, Portuguese, and a few words and rules in several other languages including Russian, Serbo-croatian... before finally taking up computer languages and becoming a programmer. In the last 5 years I have been translating a lot of Spanish and Catalan (although I can't 'speak' Catalan)... because I found 10 years ago that my roots originate from Barcelona.
Numbers in Japanese
Whilst studying Japanese I really explored the numbers... there are two systems - the first based on old Japanese numbers and the second 'borrowed' from Chinese.
J: hito-, futa-, mi-, yo-, i-, mu-, nana-, ya-, kokono-, tou (10) .... 20 = hatachi
C: ichi, ni, san, shi, go, roku, nana (shichi), hachi, ku, juu... 20 = ni juu
Note here that I do not write hitotsu, futatsu, mittsu, etc. This is because the -t(su)tsu ending is a counter, not part of the number. It is a counter for single units. In my classical Japanese dictionary:
ya- = 8 (the translocation (転) of yo- (4)
ya-tsu- (八つ) = 8
ya-so- (八十) = 80
ya-ho- (八百) = 800 - yahoka = 800 days
ya-chi- (八千) = 8000
ya-yorozu- (八万) = 80,000
ya-ho-yorozu- (八百万) = 8,000,000
The Japanese numbers are used for counting small numbers of objects (hitori = 1 person, futari = 2 people, sannin = 3 people; hitotsuki, futatsuki = 1 month, 2 months; hitokoto = 1 word; hitotabi, futatabi = once, twice; hatachi = 20 yrs (instead of ni juu sai)). Remnants of indigenous Japanese counting systems... (and Steve Trussel has a nice long list of them).
I was looking for patterns... was it coincidental that 2x mitsu = mutsu? and 2x yotsu = yatsu?
Here's a table of Japanese numerals... which can be found via Wikipedia or elsewhere these days
In Korean there is a similar set of numbers:
K: hana, tul, set, net, taseot, yeoseot, ilgop, yeodeol(p), ahop, yeol... then yeol-hana, yeol-tul ...
C: il, ee, sam, sa, o, yuk, chil, pal, gu, ship... then ship-il, ship-ee, etc
Korean numbers go further than Japanese... but beyond 100 the words become archaic and one will probably never come across them... except in pre-16th century texts
I've never really looked for the patterns in Korean.. but here are some that come across to me...
3,4,5,6 all end in -s - 7,8,9 end in -o(l)p .. 10s (from 30) end in -heun, -un
3 is set
4 is net maheun
5 is taseot
6 is yeoseot
7 is ilgop - 70 is ilheun
8 is yeodol(p) - 80 is yeodeun
9 is ahop - 90 is aheun
The differences here are similar to the changes made in English. Three-Thirty, Four-Fourty, Five-Fifty, Six-Sixty etc - some small changes to the root to accommodate the affix...
I'll need to investigate the Korean numerals further...
Most countries in South-East Asia also have two numbering systems... native and sino. Where these numbers stop depends on the country.
Cambodian native numbers are used up to about 20-30, then numbers of Chinese origin are used. Notably in Khmer 6-9 are formed simply from 5 + 1-4 - perhaps a remnant of finger counting... 20 (mpei) is possibly formed from muay and pei(/phey), 39 may be mpei dop bram buon (20 + 10 + 5 + 4) and 49 = bipei bram buon (2x20 + 5 + 4)
I suggest that the use of native numerals in all countries is very strong... but the ability to count in very large numbers becomes weaker and more long-winded compared to the Chinese numerals. In markets and trading, tradesmen would have picked up the Chinese counting system as more as more convenient for accounting for larger numbers. The Cambodian system does not lend itself to larger numerals which become ever more long-winded. Japan's older numeral system would be very confusing in situations where Sino-Japanese numbers are used, if only because ICHI is 1 in Chinese, but 5000 in old Japanese.
What little Thai I picked up regarding numerals appeared to run the same way... small numbers were native and larger numbers Sino-Thai.
Indian numbers resemble European more than Chinese... and Western numbers 1, 2, 3 are their Arabic equivalents turned on their side... ١٢٣
Tibetan numerals appear to be based on Chinese... I will need to investigate these further.. it's made a little harder because Tibetan was quite hard to learn to read... But from certain transliterations on the internet I can see a more Chinese influence than Sanskrit which Tibetan script is based on.
More another time...