Want and need have both been accepted translations of chahiye in other sentences, but need wasn't accepted here. Is there a best translation of chahiye among these options?
Out of curiosity, do you remember if you entered "You need to sleep" or "You need sleep"? The former is a valid translation.
When चाहिए is used along with the infinitive form of a verb (here-सोना-to sleep), it becomes 'need to' or 'should' (i.e [verb]+चाहिए=should [verb]) .
चाहिए is want/need when used with a noun (i.e, [noun]+चाहिए=need [noun]). But 'सोना' does not mean the noun 'sleep' so "You need sleep" is not a correct translation to this sentence.
However, as Pramod454198 has pointed out, सोना has another unrelated meaning - the noun 'gold'. So, the sentence तुम्हें सोना चाहिए can be used to demonstrate the second meaning of चाहिए as well and be translated as "You need/want gold".
Sam362597, your post is a month old, so you might have figured it out by now. Sorry, if my response is redundant. My modest input: In a construction "infinitive form of the verb +चाहिए", the word चाहिए means "should" - for example: "सोना चाहिए - should sleep", or "जाना चाहिए - should go". While in the meaning of want /need infinitive + "चाहती (f.), चाहता (m.), चाहते (pl.)" forms are used.
Thanks for this. It's weird that Duo's the first learning resource that's set it out in the this way - even Rupert Snell's TY Hindi doesn't give 'should' as a translation for 'chahiye' ... only 'need' and 'want'.