The verb चाहिये (chahiye) generally means “to be wanted”, “to be needed”, or “to be required”, etc.
चाहिये (chahiye) may also be spelled as चाहिए (chahie).
चाहिये inflects according to its number:
चाहिये is used with singular subjects, whereas चाहियें is used with plural subjects.
However, many speakers use चाहिये with both singular and plural subjects.
Otherwise, चाहिये is an invariant form and does not inflect.
चाहिये is always used in indirect verb constructions.
Thus, the subject of the equivalent English sentence becomes the indirect object in the Hindi sentence and is followed by the postposition को; likewise the object of the corresponding English sentence becomes the subject of the Hindi sentence and चाहिये agrees with it.
There are two basic idioms which utilize चाहिये:
The basic form is: [noun] + को + [noun] + चाहिये Literally, “to X, Y is needed”, e.g. “to me, money is needed” = “I need money” Examples आपको क्या चाहिये – “What do you want/need?” आपको कितनी किताबें चाहियें – “How many books do you need?” मुझे एक किताब चाहिये – “I need one book”
चाहिये versus चाहना
चाहिये implies a need more so than a desire, whereas चाहना implies a desire more so than a need. Although चाहिये may appear like a polite imperative form of चाहना, this resemblance is coincidental.
चाहिये may also imply obligation. The basic idiom is: [noun] को (noun) [infinitive] चाहिये Literally, “to X, to do Y (to Z) is needed”, e.g. “to me to eat some food is needed” = “I should eat some food” The first noun represents the person who is obligated.
The optional second noun is the object of the infinitive.
The infinitive expresses the action which is obligatory.
If the infinitive has an object, it must agree with its object in number and gender.
This is analogous to ergativity in Hindi. Thus को functions as an agentive postposition, and the verb agrees with the object, not the “subject”.
Thus, for example:
तुम्हें हिंदी सिखने की कोशिश करनी चाहिये – “You should try to learn Hindi”
Note that the infinitive करनी is feminine and singular because the agent तुम is “blocked” by को (तुम + को = तुम्हें) and when the agent of a conjunct verb like कोशिश करना is blocked by a postposition, the conjunct verb agrees with the conjunct noun, which in this example is feminine (कोशिश). See the article on conjunct verbs for more information.
मुझे कुछ खाना खाना चाहिये – “I should eat some food”
आपको उससे बात करनी चाहिये – “You ought to talk to her”
उन्हें ये काम ख़त्म करने चाहिये – “They should finish these jobs”
This idiom may be expressed in the past tense by appending an appropriate form of था (past tense of होना, “to be”):
मुझे कुछ खाना खाना चाहिये था – “I should have eaten some food”
आपको वहां जाना चाहिये था – “You should have gone there”
With Subordinate Clauses
Also, a subordinate clause may be introduced:
[person under obligation] को चाहिये कि [subordinate clause indicating what is obligated to do]
हमें चाहिये कि एक दुसरे कि मदद करें – “We ought to help each other”, literally “It is expected/needed of us that we should help each other”
infinitive + चाहिए without को
In certain circumstances, the को can be omitted when using an infinitive with चाहिए. The को can be omitted with intransitive verbs (such as होना, रहना). If the को is omitted, then the infinitive agrees with its “subject”, and not with its object. The usage without को is generally only used with inanimate, impersonal subjects; the को implies a certain moral obligation upon an agent, whereas impersonal subjects, of course, are not under any obligation. So, for intransitive verbs with impersonal subjects, the को may be omitted.
वाक्य सही होने चाहिए – “The sentences should be correct”
पानी गरम होना चाहिए – “The water should be warm”
किताब यहां रहनी चाहिए – “The book should remain here”