"De" or "Como"?
I just learned a new sentence:
"De niño, yo dormía mucho." (As a child, I used to sleep a lot)
I would like to know:
(1) How to say "As a child, Tommy learns by playing games"?
(2) How to say "Since a child, Tommy has been learning by doing things"?
(3) How to say "When Tommy was a child, he was very playful"?
(4) When to use "de" or "como"?
(5) Is it always unnecessary to use "un/una" when I say "As a child/student/parent, ..." ?
5 Answers
"As a child, Tommy learns by playing games"? sounds wrong to me in English.
Same thing with "Since a child, Tommy has been learning by doing things"?
Would you really use them like that?
"When Tommy was a child, he was very playful" = Cuando Tommy era chico/un niño, era muy juguetón.
I agree with chileno for the most part. I can imagine a situation where your first sentence would make sense. But chileno suggestion is better.
There are a ton of expressions that I hear and can understand but would never use. It is better to think about how you would say something and use forms that you are comfortable with rather than trying to understand every nuance of the language and adopt language that is not natural to you.
For example the two sentences in your first two comments are you talking naturally. Translate these and use them.
I don't know how to say "The man talks as if he were a child" in Spanish. Would you please tell me?
El hombre habla como fuera un niño. is my best guess for your sentence above.
I got this by putting your sentence above into the translator: So I was pretty close.
El hombre habla como si fuera un niño.
"De niño, yo dormía mucho." (As a child, I used to sleep a lot)
This is a perfect translation.
"Since a child, Tommy has been learning by doing things"?
For this I would say "Since childhood" / "Since he was a child" .......... "Desde su niñez" / Desde que era niño".
Concerning "De niño"
I think that you might understand it better as "from [the time he was a] child", but this is obviously an expression that does not translate directly into English.
To make it less frustrating you might try posting your attempts at translating each of your sentences in Spanish and English and see what native speakers like chileno suggest. Maybe you can come up with several ways to use de, como, cuando, desde in your sentences.