at a zero-to-eighteen-month level of a typical development (article use)

[GoesStation]

My try: There're are
many intermediate levels.
…

If somebody asked me Where're are you? ….

Don't write "there're" except in quoted dialog. "Are" is stressed in "Where are you?" so no contraction is possible.

[jutfrank]

Frankly, I still can't convince myself by this analysis.

Okay, that's fair enough.

I've also found this thread (https://www.usingenglish.com/forum/t...rmediate-level) where two English teachers say intermediate level doesn't require 'a' at all. I'm a bit confused.

No, that's right. It doesn't. I'm not sure what you mean by 'require'.

[Alexey86]

Okay, that's fair enough.

What's wrong with my floor metaphor? Would you suggest any helpful metaphor please?

No, that's right. It doesn't. I'm not sure what you mean by 'require'.

5jj says ''No article is necessary there.'' I take it to mean that both intermediate level and an intermediate level are possible.

But level is a singular countable noun. We use articles with such nouns, except for cases like level five or page three. That's why I'm confused.

[Piscean]

What's wrong with my floor metaphor? .

If we know that a person is on the fifth floor of a building, we know precisely where they are. The floors are discrete; there is no overlapping.

If we know that a person's English is at intermediate level, we do not know precisely how good their English is. A person who has just reached this level may be only marginally better than a very good pre-intermediate-level person. Another might be almost at advanced level.

So, there is no precisely defined intermediate level in the way that there is a precisely defined fifth floor.

[Alexey86]

If we know that a person is on the fifth floor of a building, we know precisely where they are. The floors are discrete; there is no overlapping.

If we know that a person's English is at intermediate level, we do not know precisely how good their English is. A person who has just reached this level may be only marginally better than a very good pre-intermediate-level person. Another might be almost at advanced level.

So, there is no precisely defined intermediate level in the way that there is a precisely defined fifth floor.

But when we say that water boils at a temperature of 100 degrees Celsius, the temperature is precise, but we still use 'a'. That's what confuses me.

[Piscean]

I'll let jutfrank deal with that. He has more patience and stamina than I.

[emsr2d2]

For me, "Water boils at a temperature of 100 degrees Celsius" is a shorter way of saying:

Water boils at a specific temperature. What temperature? 100 degrees Celsius.

The same construction appears all over the place. For example, "Planes generally fly at a height of 30,000 feet", "I will worry when he reaches a weight that equals his older sister's", "Motorways have a speed limit of 70mph".

[Alexey86]

I'll let jutfrank deal with that. He has more patience and stamina than I.

I understand. I would also leave this thread if it became a place only testing my patience and stamina.

[Alexey86]

For me, "Water boils at a temperature of 100 degrees Celsius" is a shorter way of saying:

Water boils at a specific temperature. What temperature? 100 degrees Celsius.

I can apply this logic to the floor example: I'm on a certain floor. What floor? The fifth one. => I'm on the fifth floor.

So, why does a specific temperature lead us to a temperature of 100 degrees, while a certain floor doesn't lead us to a fifth floor?
Or, what am I missing?

[jutfrank]

So, why does a specific temperature lead us to a temperature of 100 degrees, while a certain floor doesn't lead us to a fifth floor?
Or, what am I missing?

I feel I'm failing dismally to explain this. I'll try one last approach, using your 'floor' analogy.

Let's leave naturalness aside completely for a moment and compare these two sentences:

He's on the fifth floor.
He's on a fifth floor.

What does the second sentence mean? Well, it can mean either of the following:

a) The building that he is in has more than one fifth floor, and he's on one of those fifth floors.
b) The building that he is in has only one fifth floor. This particular fifth floor is just one instantiation of many possible instantiations of fifth floors.

It seems to me that you are stuck in interpretation a), which obviously doesn't make a lot of sense. In fact, to go further, to you it makes no sense at all because in your 'floor' model, it is not possible for a building to have multiple fifth floors.

This should then lead you to adopt interpretation b), which is what I've been trying to suggest. Using the 'floor' analogy, we can imagine that the world consists of multiple buildings, all with fifth floors, and he's on one of them.

I really don't think I can put it any clearer than that.