Would you find "Je suis super-héros" as something childish, too?
Equally childish, yes. Another awkward thing to say would be Il est savant-fou
, for instance (un savant fou = "a mad doctor / mad scientist"). I can only think of two occasions where it would be acceptable: 1.
a child saying Je veux être
+ a job (with the "job" being whatever a child may fancy as a job, including a mad doctor), and 2.
a gamer playing an RPG and saying that his character's class / job is "savant-fou" : Je suis savant-fou, Je suis sorcier, Je suis soldat,
Also, I find results on Google for "Je suis humain", but I find NOTHING for "Je suis être humain"; it seems like you have to add "un" here. I don't understand this, either.
With an adjective, no article is required: humain
can be an adjective, so you can say Je suis humain
(just as you might say Je suis beau, je suis blond
On the other hand, an article is needed if you're using a noun. If you're using the word humain
as a noun, you should say Je suis un humain
(the same thing happens in English: I'm human
[adjective] and I'm a human
[noun] are both equally correct).
(human being) is a nominal group, so it requires an article : Je suis un être humain
I strongly recommend you to forget about the rule saying that no article is needed when the verb is être
. This is highly misleading. Most of the times, when an article is needed in English, it's needed in French too: I'm a hero, I'm a man, I'm a friend of John's
The most common exception is jobs
: the article is optional in French because jobs are pretty much considered as adjectives. So the most common way to translate I'm a doctor
is Je suis médecin.
Note that the article is optional with jobs, but it's not incorrect to use it. The difference between Je suis médecin
and Je suis un médecin
is the same as the difference between I'm human
and I'm a human
in English, or I'm American
and I'm an American
. In other words, leaving out the article is more common, but adding it is required if you wish to add something else: I'm an ordinary human
("Je suis un humain ordinaire").