# Japanese/Existence and Copula
## What is a copula?

In English, the verb 'to be' serves two purposes: It acts as the copula, and it acts as the verb for existence. However, in many languages, including Japanese, these two verbs are separate—so it helps to have an understanding of the difference between the two usages.
A copula can be thought of as an equals sign: it equates two things to each other. In the sentence "That is a dog," 'is' is the copula. In the sentence "The dog is inside," you don't mean that 'the dog' and 'inside' are the same thing; you mean that the dog exists inside.
These two usages have different verbs in Japanese, so it'd be good to get used to it now. Here are some examples:
Using 'to be' as a copula:
* That man is the president.
* Joe is a salesman.
* The dog is a golden retriever.
* This paper is my report.
Using 'to be' to mean existence:
* Sara is outside.
* The plate is on the table.
* The watch is on my wrist
* They are at the mall.
* There is John.

### Origin of copula
#### で ある, or だ

    to be (am, is, are)
    The verb だ is a contraction of the で ある, which can replace the full form in any sentence, except in front of sentence-ending particle か, as will be noted later. The full form is mainly used in formal literature, such as a Wikipedia article. The ある verb itself means "to be, to have, to exist“, and で is a grammatical particle meaning "with". Adding these two words together into である literally translates as "existing with". Because all particles must take a noun, the Japanese である can not be used as widely as its English counterpart: である may only be used to describe attribute, not action (i.e., it cannot be used in constructions like "I am doing something" as a translation of "am").

## The Japanese Copula

In Japanese, です (desu) is the copula. It is used to equate two things. Let's look into translating the sentence, "That is a pen," into Japanese.
Japanese uses subject-object-verb word order. This means that the copula and all other verbs come last in the sentence, after the object. If we were to form the English sentence in this way, it'd go like this: "That a pen is." This is a little unclear without some separation between the subject and the object. This brings us to particles.
Particles are small words which are simply used to denote what role a word plays in a sentence. There are quite a few particles, but we'll only concern ourselves with one of them for now—the topic marker, は (wa)*. This particle marks the topic and subject of the sentence. Incorporating this into our example, our sentence would become: "That は a pen is."
Finally, in order to complete the conversion to Japanese, we just need to translate the words themselves. 'Is', as I mentioned above, becomes です (desu). We can use それ (sore) and ペン (pen) for 'that' and 'pen', respectively. Now, our sentence is "それはペンです。" (sore wa pen desu.), which is a complete, understandable Japanese sentence.
* The topic-marker, は, is prounounced 'wa' even though it is written with the kana for 'ha'.

## Existence

The other usage of the verb 'to be' is for existence. This gets slightly more difficult, as there are two verbs for existence: いる (iru) and ある (aru). Don't worry, though, it's pretty easy to differentiate between the two. いる (iru) is only used for animate objects, whereas ある (aru) is only used for inanimate objects. For example, you'd use いる (iru) for yourself, another person, or an animal, whereas you'd use ある (aru) for practically anything else, such as a pen, some paper, or a book.
In order to say, "I exist," or, "I am," (a sentence which will come in much more handy later) you'll follow a formula similar to what you did for the copula above. The verb always comes last, and the subject is marked with the topic marker, は (wa). わたし (watashi) is the pronoun for 'I', so the sentence, "I am," becomes "わたしはいる。" (watashi wa iru.).
You can use this exact form to say "the pen exists", but keep in mind that the pen is inanimate, so you must use ある (aru). The sentence becomes "ペンはある。" (pen wa aru.).