What's the difference between ～しか～ない and ～だけしか～ない?


Two ways of expressing 'only' in Japanese are だけ + positive verb and しか +
negative verb. For example, the following sentences both translate to
something like 'I drank only tea'.

  * お茶だけ飲んだ (1)

  * お茶しか飲まなかった (2)

I recently heard a native speaker use だけしか + negative verb, and Google brings
up plenty of hits for this construction. For example:

  * お茶だけしか飲まなかった (3)

Is there any difference in meaning between sentences (2) and (3)? Does
including 'だけ' just add emphasis?




Is there any difference in meaning between sentences (2) and (3)? => Not
literally/factually

Does including 'だけ' just add emphasis? => Yes - see on

しか =＞ used when more is expected

だけ ＝＞ does not have this nuance

eg

> 一問しか間違えていなかった。
>
> There was only one mistake
>
> 一問だけ間違えていた。
>
> There was just one mistake

=> だけしか ＝ no more than just....

_Reference: A students' guide to Japanese Grammar by Naomi Hanaoka McGloin, p
70-77 covers the difference between だけ＆しか._

