Confused in choosing 早い versus 速い


In my understanding, 速い is used for motion and 早い represents "early".

Which one is the correct one in this example?

> A: 授業がそろそろ始まるので、 **早く** 来てください。
>
> B: 授業がそろそろ始まるので、 **速く** 来てください。




Your understanding is correct. 速い refers to one's speed and 早い refers to time.
However, 早い has more uses than just meaning early. Check: [How to distinguish
between the meanings of "quickly", "soon" and "early" for
早く](https://japanese.stackexchange.com/questions/6999/how-to-distinguish-
between-the-meanings-of-quickly-soon-and-early-for-%E6%97%A9%E3%81%8F). 早く来る
would mean coming quickly with the focus on getting there on time, not
particularly on getting there with speed. For example:

> 早く憲法改正してください。

Please amend the constitution quickly, which emphasis on getting it done
before it is too late. 早く also means to "hurry up," as in the case with coming
to class early, or the passage of the amendment, or 「早く質問しろよ」. In your
example, 早く would make the most sense.

<http://dictionary.goo.ne.jp/jn/179400/meaning/m0u/> Check the dictionary for
more detail. 早い has many more definitions than 速い.




Your understanding is correct. 速い refers to one's speed and 早い refers to time.
However, 早い has more uses than just meaning early. Check: [How to distinguish
between the meanings of "quickly", "soon" and "early" for
早く](https://japanese.stackexchange.com/questions/6999/how-to-distinguish-
between-the-meanings-of-quickly-soon-and-early-for-%E6%97%A9%E3%81%8F). 早く来る
would mean coming quickly with the focus on getting there on time, not
particularly on getting there with speed. For example:

> 早く憲法改正してください。

Please amend the constitution quickly, which emphasis on getting it done
before it is too late. 早く also means to "hurry up," as in the case with coming
to class early, or the passage of the amendment, or 「早く質問しろよ」. In your
example, 早く would make the most sense.

<http://dictionary.goo.ne.jp/jn/179400/meaning/m0u/> Check the dictionary for
more detail. 早い has many more definitions than 速い.

