Where does です come from?


I've heard various things about this construction from many different people,
a few examples of which are:

  * It's a verb meaning "to be".
  * It's a contraction of something like でございます (de gozaimasu) or ではあります (de wa arimasu).
  * It just kinda appeared as a "polite" marker.

Could anyone here offer a succinct explanation of what it actually means?




I think to answer your question it needs to be broken into two parts, namely
"what is です's etymology?" and "where is です used?".

## Usage

You will see です used in two ways:

  * As the polite form of the copula だ. In this case, it has the meaning "to be" and acts mostly like a verb, in that it inflects.

> 彼{かれ}はお医者{いしゃ}さんです。 "He is a doctor."
>
> ちょっと変{へん}でした。 "It was a little weird."

  * As a polite marker for i-adjectives. Historically, i-adjectives had a polite inflection, [〜うございます](https://japanese.stackexchange.com/q/765/78), which showed up as late as the 1960s, but it was thought to be "too polite" in many cases and was eventually discarded. However, the non-polite form was considered to be too impolite, so 〜です was added on the end as a polite marker. It is not the copula here and as a result does not inflect.

> 楽{たの}しいです。 "It is fun."
>
> 熱{あつ}かったです。 "It was hot."

## Etymology

Although there are many theories about the origin of です, the common one among
linguists I know is that it is a contraction of でございます. However there are
competing theories (でそう、であります) and there is not yet a consensus about the
correct one.




I think to answer your question it needs to be broken into two parts, namely
"what is です's etymology?" and "where is です used?".

## Usage

You will see です used in two ways:

  * As the polite form of the copula だ. In this case, it has the meaning "to be" and acts mostly like a verb, in that it inflects.

> 彼{かれ}はお医者{いしゃ}さんです。 "He is a doctor."
>
> ちょっと変{へん}でした。 "It was a little weird."

  * As a polite marker for i-adjectives. Historically, i-adjectives had a polite inflection, [〜うございます](https://japanese.stackexchange.com/q/765/78), which showed up as late as the 1960s, but it was thought to be "too polite" in many cases and was eventually discarded. However, the non-polite form was considered to be too impolite, so 〜です was added on the end as a polite marker. It is not the copula here and as a result does not inflect.

> 楽{たの}しいです。 "It is fun."
>
> 熱{あつ}かったです。 "It was hot."

## Etymology

Although there are many theories about the origin of です, the common one among
linguists I know is that it is a contraction of でございます. However there are
competing theories (でそう、であります) and there is not yet a consensus about the
correct one.

