[Idiom] ask for sb to do / ask sb to do

[Shalvas]

Could you tell me the difference between the following 2 phrasal verbs?

1.ask for sb to do
2.ask sb to do

For example, on page 77 in "Practical English Usage 2nd Edition",
you can see this sentence:

"I asked for the children to have extra milk."

I think this sentence has same meaning as

"I asked the children to have extra milk."

I assume that both sentences says,
"I asked the children to drink every last drop of milk."
What's the difference between them?

 

[Tdol]

There's a difference in meaning.

I asked for the children to have extra milk- In this case, the speaker did not ask the children. The speaker asked someone else to arrange or make sure that the children got extra milk.

 

[Barb_D]

Also, your association between "extra" and "every last drop" is not sound.

Extra just means "more than they usually have."

If they usually have one cup and today they had two, but left a little bit in the bottom of their glasses, they still followed your command.

 

[Shalvas]

Now it all makes sense to me.
Thank you very much.