In many languages including English, the words of number are used for counting directly.
But, Japanese need to add an appropriate unit word to the number.
And there are a lot of unit words.
You must know them, but please learn commonly used words first.
Tsu – multipurpose word until 10
From 1 to 9, “tsu” is added at the end of the word. Only 10 doesn’t have it.
But each word is different from the reading of number you have already learned.
Because the reading is a way of counting since ancient times.
But you can use them for various things.
All inanimate objects are able to be counted using this “tsu”.
However, the counting is until 10.
Ko for various things
One more convenient unit is “ko”.
It is similar to “tsu”, and it is used for various things except person and animal.
Basically, “ko” is added after number.
In above yellow parts (1, 6, 100) , number and “ko” are combined for smooth pronunciation.
And when you count using “tsu”, you can use this “ko” from 11.
Nin for counting person
When counting person, “nin” is used.
Basically, “nin” is added after number.
About 1 and 2, the words based on ancient counting are used like “tsu”.
About 4, one “n” is cut out because of a succession of “n” sound.
For counting person, only this “nin” is used.
You must never use the other unit.
Hiki for counting animal and Wa for counting bird
When counting animal, fish or insect, “hiki” is used.
And, when counting bird, “wa” is used.
When the head sound of unit is “H”, a number and a unit often are combined for smooth pronunciation.
And, when the head sound of unit is “W”, the sound is changed to “B” at 1000 and 10000.
In fact, for some kinds of animal, units different from “hiki” are used.
But that is not so strict. Therefore it is OK that you always use “hiki”.
Hon, Mai, Dai
I introduced “tsu” and “ko” for counting things.
But let’s learn some units for special forms.
For long and slender thing, “hon” is used.
For example, pole, pillar, column, pen, pencil, tree, lumber, etc.
Bottle of wine and beer is also counted using “hon”.
And wire, rope, cord, rail, line are counted using “hon”.
For thin thing like sheet, “mai” is used.
For example, paper, card, DVD, blanket, thin clothes, leaf, etc.
Slice of bread and meat is also counted using “mai”.
For machine such as car, bicycle, electrical products, etc., “dai” is used.
Instrument and tool are also counted using “dai”.
Satsu, Ken, Hai
For the things of bound papers such as book, notebook, etc., “satsu” is used.
For the building which is not so big such as house, shop, etc., “ken” is used.
It isn’t used for big building.
For the number of times that you drink, “hai” is used.
Japanese people eat rice with small bowl. For the number of times that you eat rice, “hai” is used.
Chaku, Soku, Haku
For thin underwear, “mai” is used, but for suits, dress, jacket, etc., “chaku” is used.
For shoes, socks, stockings, “soku” is used. A pair of them is “1-soku” (issoku).
When you visit Japan, “haku” is used for the number of times that you stay in a hotel.
When you book a hotel, this “haku” is used.
Anyhow, it has a wider variety of units!
I introduced the units that we often use.
But there are a lot of other units in Japanese.
Nevertheless, if you command above units, your Japanese sounds like native speaker.
Anyhow, please learn these.