Translation for "When I was young"

Question

I need to say "when I was young" in reference to a male. I always forget whether the correct translation is "Когда я был молодой" or "Когда я был молодым".

Can you please explain why I need to use the first/second form?

I learned that in these cases the instrumental is used to express transitive qualities, that alter over time, while the nominative is used to express permanent qualities. So in this case it should be intstrumental, because the men has eventually grown older. However, on the internet I have found the nominative case, too "Когда я был молодой" (I think it was a song or something of the sort). I'm confused!

Answer 1

You can use three variants. Those are a full adjective in the nominative case, a full adjective in the instrumental case and a short adjective. Our celebrated linguist Розенталь describes their usage like the following but admits that the rule is not strict and some adjectives don't follow it. We use a full adjective (nominative case) to express either a constant or an absolute quality and when we don't mention the time.

Человек он был молодой и красивый. Потолок был низкий.

We use a full adjective (instrumental case) when the situation describes a certain period of time.

Когда он был молодым, мы часто встречались.

And we use a short adjective when the situation refers to a certain moment.

Он был молод, когда я с ним познакомился. Потолок был низок для купленной мебели.

But in real life these cases are not always followed and searching in the National corpus I found all the three variants after когда. But the statistics was rather interesting :

когда я был молодой --9 examples in the main part, когда я был молодым--18, когда я был молод--21.

Answer 2

Когда я был молодым sounds better, but когда я был молодой is also possible in the same meaning. But the former sounds more proper, while the latter is sooner colloquial. There is also a third possibility, когда я был молод, which sounds a bit bookish and outdated, but it vividly reveals the fact that the speaker is no longer young. ) If a not yet old man says "когда я был молод (и горяч)", he does it for the sake of humour.

Answer 3

The both are OK and it is difficult to come up with a case where they are not interchangeable. I will try.

Во сне он был молодой = He looked young while sleeping.

Во сне он был молодым = He was young in his sleeping dream.

Suppose there is a fairy tale where a magic ring makes the person young temporarily.

So,

Когда я был молодым = When he was young due to the ring, during the duration of spell. Can also mean when he was truly young.

Когда я был молодой = When he was truly young, cannot mean young due to the magic ring.

So, "Когда я был молодой" means when I was truly young, "Когда я был молодым" can mean besides truly young also young due to some factors like imagining oneself young or be temporarily young or playing a role of a young.

Когда я слышу эту песню, я становлюсь молодым = When I hear this song, I feel as a young, much better, stronger than usually. Physically change to a young man. Can mean he can date young women.

Когда я слышу эту песню, я становлюсь молодой = When I hear this song, I re-asses my current age, despite my actual age, I think of it as of quite young age. Can mean he can date women of his age as if the both were young.

Also, молодой can mean a bride or any other slang or special meaning (like young role in a play etc), so if you mean молодой as a noun, use

Когда я был молодым