Change- and unchange-of-state 了: During which time in a person's life is it correct for them to say 我三岁了 (I am 3 years old)?

Question

我三岁了
I [am] three years of age

This breaks apart as follows:

• 我 (wǒ) = me
• 三 (sān) = three
• 岁 = years of age
• 了: I understand 了 here is the change-of-state 了: prior to turning 3, I was not 3, so that state has changed.

I have two points of confusion regarding when it's correct to say 我三岁了:

1. • Two years old: 我三岁了 is incorrect because... (why?). It seems correct to say e.g. 明年我三岁了. It seems theoretically possible that 我三岁了 could refer to a future change of state (although surely none would use it because it's misleading).
   • Three years old: 我三岁了 is correct: I turned 3 (change of state). [more about this in point 2.]

   • Four years old: 我三岁了 is grammatically incorrect: my best guess as to why is because while I turned 3 (change of state), I subsequently also turned 4 (unchange of state). With this reasoning, 我去年三岁了 is self-contradictory (maybe?). And Baidu indicates it's correct to say

     我去年三岁
     Last year, I was three years of age

     without the change-of-state 了.

2. When I'm three years of age, for that full year, I'm not sure if it's okay say 我三岁了. For example, I wonder if it's okay to say

   我三岁了，明天我四岁了.
   I [am] three years of age, tomorrow I [become] four years of age

   The change of state happened a long time ago, so I'm unsure if it still counts as a change of state (but maybe a change of state has no expiry).

Question: During which time in a person's life is it correct for them to say 我三岁了 (I am 3 years old)?

Answer 1

Correct for "change".

• Usually say 我三岁了 on the birthday of three. That's the day of change.
• When four years old, remove 了 as past not change.
• On the birthday of four, we usually say 我三岁，明天我四岁了, as there is no change for the first part.
• Any other cases for "change" during the year of 3? Yes. When someone asks the little cute toddler that "r u 2 years old", the cute will reply nooooo, 我三岁了 proudly, to indicate the "change".

Answer 2

1. • Two years old: 我三岁了 is incorrect because... (why?). It seems correct to say e.g. 明年我三岁了. It seems theoretically possible that 我三岁了 could refer to a future change of state (although surely none would use it because it's misleading).

Yes, it's incorrect, because... you're still 2 years old. Note that 明年我三岁了 is correct, but 我三岁了 always refers to now unless specifying adverbial of time explicitly like 明年 or 去年.

• Four years old: 我三岁了 is grammatically incorrect: my best guess as to why is because while I turned 3 (change of state), I subsequently also turned 4 (unchange of state). With this reasoning, 我去年三岁了 is self-contradictory (maybe?). And Baidu indicates it's correct to say

  我去年三岁
  Last year, I was three years of age

  without the change-of-state 了.

Here 我三岁了 is incorrect, at least misleading. People won't consider you've been 4 years old when hearing that. 我去年三岁 is correct, and 我去年三岁了 is correct too, which puts the emphasis on the fact that the change of state happened in 去年. Especially when you want to emphasize that I've been 3 years old long ago you can say 我去年就三岁了 or even 我前年就三岁了.

2. When I'm three years of age, for that full year, I'm not sure if it's okay say 我三岁了. For example, I wonder if it's okay to say

   我三岁了，明天我四岁了.
   I [am] three years of age, tomorrow I [become] four years of age

   The change of state happened a long time ago, so I'm unsure if it still counts as a change of state (but maybe a change of state has no expiry).

我三岁了，明天我四岁了 is fine. (Adding 就 sounds more natural to me like 明天我就四岁了.) I feel that you don't need to care about the period of validity of the change of state, the point is the current state. You're in the state of 3 years old, then it's always fine to say 我三岁了.

Answer 3

You can say "我三岁了" in a present tense from the day you turn three to the day before you turn four

At any age younger than three, you cannot say "我三岁了" without referring to the change of state is in the future e.g. 明天我就三岁了

At any age older than three, you cannot say "我三岁了" without referring to the change of state was in the past e.g. 人類登陸月球時我已經三岁了，當然有看過直播 (I was already three years old when humans landed on the moon, of course I have watched the live broadcast, )

When people ask you: "how old are you" you can answer either: "我三岁了" (directly stating you are currently three years old) or "我明天四岁了" (indirectly indicate you are currently still three years old)

"我三岁了，明天我四岁了" are two disjointed sentences

If you insist on stating the two facts (I am 3 already + I will be 4 tomorrow) in one sentence, you can do that, but only one 了 and one 我 is needed

"我三岁，不過明天就四岁了" (I am three, but I will be four tomorrow).

The single 我 is the subject of both facts

The single 了 at the end applies to both facts

One more example:

(fact 1) 我了退休了 (the first 了 is an aspect marker indicate the verb retire is completed, the second 了 is a final particle indicate change of situation)

(fact 2) 我明天起不用工作了 (了 is a final particle indicate change of situation from need to work to don't need to work)

我退了休，明天起不用工作了

Answer 4

In 我三岁了, 了 can be construed as either the state of change or completion(already) according to contexts.

E.g.

A: 你几岁了

B: 我三岁了

In this case, B simply means I'm three years old already. He doesn't indicate the change 2->3. He just tries to tell the truth that he is being 3 years old now.

Another example, say today is your birthday, you can say 我三岁了 to indicate that now you have reached 3. In this case, the change 2->3 is implied.

I might think the-state-change 了 only works well for present. It doesn't work well for past and future. E.g. 下雨了，成功了，我们胜利了，etc. I would prefer not to use 了 in the sentences like 我明年三岁了 and 我去年三岁了. I might as well say 我明年三岁 and 我去年三岁.

I think the reason why the-state-change 了 works well for the present is that it can add some effect of exciting, surprise, joyfulness, happiness, etc.. Using it in the past or future, people won't feel the effect. Thus, it becomes redundant there!

If you want to emphasize the change in the future or past, we can add 就 for effect. E.g. 我明年就三岁了，我去年就三岁了. Without 就, the effect would be lost.

My two cents.

Answer 5

You can say 我三歲了 after you have been born for more than three years but not reach four years.

If you feel not safe to use this, you can use 我已經滿三歲了.