Although だけ and しか are both particles in Japanese that express a sense of limitation or restriction, they differ in their usage and meaning.
The particle だけ (dake) is used to indicate “only” or “just” and is used to specify the extent or limit of something. It can be used with both nouns and verbs and is usually placed after the noun or verb it modifies. Here are some examples:
私は一日にコーヒーを一杯だけ飲みます。
I only drink one cup of coffee a day.彼女は、勉強する時間が一時間だけあります。
She has only one hour to study.
On the other hand, しか (shika) is used to express a negative limitation, indicating that something is the only option or choice available. It is typically used with negative verbs and adjectives to indicate that there is no other alternative. Here are some examples:
私はコーヒーしか飲みません。
I only drink coffee (and nothing else).彼女は寿司以外は何も食べません。
She doesn’t eat anything except for sushi.
In these examples, しか (shika) is used to indicate that there is no other choice or option available besides the one mentioned.
Another difference between だけ and しか is that だけ can be used in comparative constructions to indicate a slight difference in degree or quantity. For example:
この部屋は、前の部屋よりほんの少し広いだけです。
This room is only a little bit wider than the previous room.
In this example, だけ (dake) is used to indicate that the difference between two things is only a slight degree.
In contrast, しか (shika) is not used in comparative constructions, as it expresses a negative limitation rather than a degree of difference.
In summary, the key difference between だけ and しか in Japanese grammar is that だけ is used to indicate a limit or extent of something, while しか is used to express a negative limitation, indicating that there is no other alternative or option available besides the one mentioned. Additionally, だけ can be used in comparative constructions to indicate a slight difference in degree or quantity, whereas しか cannot be used in this way.