Hindi has a set of related idioms that are sometimes called “compulsion idioms”. In other words, they describe the concepts of “have to”, “must”, “should”, and “ought to” in English.

There are three primary idioms; one idiom involves the verb होना, one idiom involves the verb पड़ना, and one idiom involves the verb चाहिए. Each idiom uses an infinitive.

Each idiom has a similar form:

This idiom has the form X को [infinitive] [form of होना / form of  पड़ना / form of चाहिए].

In each idiom, both the verb and the infinitive agree with the object of the infinitive (e.g. “मुझे रोटी खानी है”). If a nominal conjunct verb is used and the object is unexpressed or followed by a postposition, then the verb of the conjunct verb agrees with the noun of the conjunct verb (e.g. तुम्हें उससे बात करनी है). This also cascades to complementary infinitives (e.g. मुझे रोटी खानी बंद करनी पड़ी). This is analogous to ergativity (a.k.a. -ने verbs) in Hindi: the agent is “blocked” by a postposition, so the verb agrees with the object, not the subject.

Infinitive + होना

This idiom has the form X को [infinitive] [form of होना]. This idiom is generally used under the following conditions:

• The compulsion is mild or incidental
• The compulsion did not arise because of some circumstance

These are general principles, and not absolute rules.

It’s also important to note that this form is used to express things other than compulsion, especially in colloquial Hindi. In can be used to express a want or desire (e.g. “I want to …”), and also as a periphrastic future verb (e.g. “I am going to …”, or “I was going to”).

For instance, it’s very common in colloquial Hindi to hear something like “(मुझे) चाय पीनी है” – “I want to drink some chai”. This is not a compulsion (i.e. “I have to drink some chai”), but a desire.

As another example, in colloquial Hindi, it is common to hear something like “मुझे बस इतना बोलना था कि मुझे तुम्हारे घर आने में थोड़े देर हो जाएगी” – “I just wanted to say that I’m going to be a little late coming to your house”, or “I was just going to say that I’m going to be a little late coming to your house”, etc.

More information is available about the “infinitive + होना” verb form here.

Examples

Consider the following examples of this compulsion idiom:

मुझे जाना है – “I have to go”

अगर आप हिंदी सीखना चाहते हैं तो आपको बहुत कठिन मेहनत करनी होगी – “If you want to learn Hindi, then you’ll have to do a lot of hard work” [NOTE: in this example, पड़ना could have been used. There is not always a strict distinction between the two idioms.]

Notice that a feminine infinitive (करनी) and a feminine verb (होगी) were used in the previous example because मेहनत is a feminine noun.

Infinitive + पड़ना

This idiom has the form X को [infinitive] [form of पड़ना]. It is generally used under one or both of the following conditions:

• The compulsion is stronger, something that is necessary or forced
• The compulsion arose because of the circumstances

These are general principles, not absolute rules.

Examples

हमें पैसा कमाने के लिए काम करना पड़ता है – “We have to work to earn money”

नाव को आग लग गयी इसलिए हमें नाव से बाहर कूदना पड़ा – “We had to jump out of the boat because it caught fire”

जो वादा किया वह निभाना पड़ेगा – “You must fulfill what you promised” (Song title)

Infinitive + चाहिए

This idiom has the form X को [infinitive] [form of चाहिए].

Like “should”, or “ought” in English, this idiom expresses a moral obligation, duty, propriety, expediency, advantage, etc.

It is generally not used when asking questions such as “What should I do?”. For this, the subjunctive mood is used: मैं क्या करूं – “What should I do?”. However, some speakers do use this idiom in such questions.

Examples

मुझे पिछले साल भारत जाना चाहिए था – “I should have gone to India last year”

Note that a past tense form of होना (e.g. था) can be used to indicate “should have …”, etc.

हमें बड़े लोगों को सम्मान देना चाहिए – “We should respect elders”