The postposition ne is often misused and even more commonly misunderstood by learners of Hindi, due to most grammars not wanting to get into the real issue at hand, the topic of Ergativity. This explanation is somewhat technical, relying on linguistics terms, but if you grasp the concepts in this article, your ability to use ne properly will increase dramatically.

The first step to understanding ne is to be clear on the distinction between a transitive and an intransitive verb. It is actually rather simple: A transitive verb is something acting on something else, that is, has a "subject" and an "object," an intransitive verb does not. In English, a great many verbs can be transitive or intransitive. In Hindi the distinction is firmer. There are a few verbs in English with a hard and fast distinction between transitive and intransitive, such as the intransitive rise and the transitive raise (Which, as can be seen from the similarity, are related, just like most Hindi transitive/intransitive pairs are related)

Unfortunately, even thinking in terms of subjects and objects can cause confusion, there are actually three relevant categories that should be considered in order to clarify things. The term introduced will be "Experiencer," to describe the grammatical subject of an intransitive verb. (The notion of "experience" should not be taken too literally here, even inanimate objects can be experiencers.) Thus, the three categories are:

• Subjects of transitive verbs (You raise the flag.)
• Experiencers of intransitive verbs (The water rises.)
• Objects of transitive verbs (You raise the flag.)

Most Western languages, like English, Spanish, or German, and even many non-Western ones, like Japanese, rely on what is known as an accusative syntax. All this means is that a transitive verb always agrees with its subject. Needless to say, an intransitive verb must also agree with the experiencer because that is the only argument of an intransitive verb . This is how Hindi is in most of its tenses, too. Just like in English where one would say "I go" but "she goes," making sure to make the verb agree, in Hindi one would say "लड़का जाता है" but "लड़की जाती है," similarly making the verb agree with the subject. Hindi requires gender agreement in its verbs where English does not, but the concept of agreement is the same: Transitive verbs agree with their subjects.

On the other hand, in the perfective tenses, that is, the tenses showing an accomplished action, everything changes. Hindi assumes what is called an ergative syntax. This is what is known as "split ergativity," where the syntax of the language varies depending on the tense. All ergative syntax really means is that transitive verbs now do not agree with their subjects, but instead with their objects. Intransitive verbs still agree with their experiencers because this is still the only thing around to agree with. The subject in the perfective tenses is always marked with ne. If there is no subject, such as if the verb is intransitive and thus only has an experiencer, no ne is needed.

Here is a concise summary:

Imperfective	Perfective
Subjects and experiencers treated alike: Verbs must agree with them	Experiencers and objects treated alike: Verbs must agree with them
Objects distinguished: Verbs do not agree, optionally marked with ko	Subjects distinguished: Verbs do not agree, marked with ne

This is all well and good, but language is rarely so logical. There are a few verbs that are not always transitive and thus can technically take both subjects and experiencers but still always take ne (even marking an experiencer with ne), such as verbs of communication like कहना, सुनना, पूछना, सोचना, and बताना, or bodily functions like खाँसना or छींकना. On the other side, there are apparently transitive verbs that do not use ne, including most compound verb forms, as well as लाना, भूलना, and बोलना. These verbs form their perfective tenses the exact same way as their imperfective tenses, agreeing with their subjects.