"Ella está un poco cansada y quiere dormir."
Translation:She is a little tired and wants to sleep.
Yes, but that would make the word "sleep" a noun instead of a verb. In the sentence it's a verb, so you have to use "to" to make the English word also a verb.
Also to interested readers:
Many of the Duolingo students who come here to read this forum web page have not yet learned that infinitives are used as nouns. If you are not yet educated in this area, take a look at the following article.
Spanish grammar lesson:
Spanish Infinitives used as the object of a verb:
She is a little tired and wants sleep. ― Ella está un poco cansada y quiere dormir.
I am not sure how you're extracting that translation out of the article you linked. The only similar thing I can find in there does use the English to-infinitive form:
As the object of a verb: Yo preferiría salir. (I would prefer to leave.)
I mean, "wanting to sleep" and "wanting sleep" basically mean the same (unless you have a sleep-stealing device), but they still use different word classes. And, at least for learning purposes, they should kept parallel.
"I am not sure how you're extracting that translation out of the article you linked...."
You misunderstood me. I did not extract a translation out of any article. Perhaps if I reveal to you who I am, you will believe me.
And now, by the authority vested in me by the State of Gotham, with this Batarang, I hereby christen the following translation as a "Bat translation". This Bat translation, shown below, is thus entitled to all the rights, privileges and honors thereunto pertaining to linguistic discourse.
The issue is how do we translate the following English sentence into Spanish.
"She is a little tired and wants sleep."
― Ella está un poco cansada y quiere dormir.
I agree with Jose296058, "to" is not required in English. That would be up to the person saying the sentence but there would be no right or wrong in this situation. The answer should be excepted either way.
To get sleep is a little different, it's like the difference between taking a showet and having a shower, but putting the word "get" might make it rather demanding and you would also have to change the spanish sentence.
I put : "She is a little tired and wants sleep", and it didn't accept it. Am I really wrong?
Yes, kind of. Semantically it's the same, but you used the noun "sleep" here. Dormir is a verb.
You are perfectly correct.
Sometimes we have to report errors when Duolingo fails to accept our answers.
I'm pretty sure the use of "little" in this sentence is not good english. I don't know if there's a rule to that effect, but I've never seen it used that way. You would use "little" in front of a noun, e.g., "she is a little devil", "she is a little girl" and "bit" in front of an adjective: "she is a bit tired", "she is a bit angry". Or even, "she is a little bit tired".
Must be a regional thing, I say "little" in front of adjectives all the time.
In the USA the word "little" is very common. The use of "bit" in place of "little" does sound a bit British but both words should be excepted. We love our British, Canadian, and Australian allies.