Correct?

[banderas]

Could you tell me the reason why you are always late.

If it is correct, then what is the difference(If there's any) between the above and the followings:

Could you tell me the reason (that) you are always late.=could you tell me the explanation for why you are always late.
Could you tell me why you are always late.= could you tell me for what reason you are always late.

Thanks.

For me both are fine.

[engee30]

I am sorry to be annoying again, but I need to know it.Did you just confirm my thought about being used by people? Yes and no.
It's more to do with grammar rules rather than what people want to think and say. What people want to think and say without taking grammar into consideration is referred to as colloquialism.

Let me say it like it is on my mind.

If the following sentence happens often in speaking, then why can't we call it a collocation? Look above.

Could you tell me the reason you are always late

Regarding that you said the reason why is a collocation, so it is the correct answer. And stick with this theory - you shouldn't be let down through using it.
Thanks.

[atlaisha]

Please correct me if I'm wrong:

-Collocation is the way people use words one after the other without violating grammer rules.

-"Tell me the reason you did it" is being used by people and it wouldn't be unusual if I use it too, but it is not grammatically accepable and that's why we don't call it a collocation.

-"Tell me why you did it" is absolutely alright.

Many thanks,

[riverkid]

It's more to do with grammar rules rather than what people want to think and say. What people want to think and say without taking grammar into consideration is referred to as colloquialism.

This is simply not true, Engee. Grammar rules do not exist independently of how people use language. You're mistaking prescriptions for grammar rules. They are fundamentally different things

Grammar rules can ONLY describe how people use language. There's nothing ungrammatical about "the reason why" so it can't have anything to do with grammar rules.

[engee30]

Please correct me if I'm wrong:

-Collocation is the way people use words one after the other without violating grammer rules.

-"Tell me the reason you did it" is being used by people and it wouldn't be unusual if I use it too, but it is not grammatically accepable and that's why we don't call it a collocation.

-"Tell me why you did it" is absolutely alright.

Many thanks,

That's the last straw, mate! You've just made me feel inclined to explain everything as clearly as possible to you.

You can talk about the reason why (= explain why) something happens or is done:

I didn't want to upset you. That is (the reason) why (= That explains why) I didn't tell you about it in the first place.

You can, however, omit the reason, and make it That's why...

You can't use a that-clause in this case, nor can you leave why out.

Could you tell me (the reason) why (= Could you explain to me why) you are always late?
The very same rule applies here, buddy.
____________________

Now, if you're, however, actually stating the reason, you do not use why. You use a that-clause instead (or leave that out):

The reason (that) I didn't tell you about it in the first place is that I didn't want to upset you.

The reason (that) I'm ringing you is that I need to ask for advice.
or
The reason (that) I'm ringing you is to ask for advice.

(the part of the sentence that is underlined is the reason being explained.)
____________________

Now compare the sentences with why and with that, and you'll see the difference - in the why sentences there is no reason being given, while in the that sentences there is.

Got it? I do hope so!

Oh, there's one more thing - because can be used in informal use instead of that (i.e. the green that). But please try to avoid such use in exams and tests:

The reason (that) I didn't tell you about it in the first place is because I didn't want to upset you.

The reason (that) I'm ringing you is because I need to ask for advice.

Surprisingly enough, that use of becuase helps a lot to know where you've got the reason explained, and therefore you know exactly where you can use that, and not why instead.

[engee30]

This is simply not true, Engee. Grammar rules do not exist independently of how people use language. You're mistaking prescriptions for grammar rules. They are fundamentally different things

Grammar rules can ONLY describe how people use language. There's nothing ungrammatical about "the reason why" so it can't have anything to do with grammar rules.

Well, that's what you think, Riverkid. This is what I think and one of the foremost authorities on the English language:

Language is grammaticalised lexis, not lexicalised grammar.
Lewis, 1993

To me, the most important thing is to split the term collocation into two subcategories, which are as follows:

1. lexical collocation
2. grammatical collocation

Examples of the above subcategories are rose wine and afraid of, respectively. The phrase the reason why, in my opinion, falls into the second subcategory.