The English language, in its rich tapestry of words and grammatical structures, often presents nuances that can befuddle even seasoned writers and speakers. Among these subtleties, the interrogative pronoun “what” frequently occupies a position of particular intrigue, especially when it comes to its functional roles within a sentence. Understanding “how what part of speech” delves into the very essence of how we form questions, seek information, and express degrees of difference or manner. This exploration will dissect the multifaceted nature of “what” as it pertains to parts of speech, focusing on its interrogative function, its relative capacity, and its less common but significant adjectival and adverbial uses, all within the realm of seeking information and defining states.

The Interrogative Pronoun: Seeking Specific Information
At its core, “what” functions most prominently as an interrogative pronoun. This role is fundamental to forming questions that seek specific information about things, ideas, or actions, rather than people. When “what” stands alone as the subject or object of a question, it directly elicits a noun or noun phrase as an answer.
Identifying the Object of Inquiry
In its interrogative pronoun capacity, “what” often acts as the direct object of a verb, prompting the listener or reader to identify a specific entity or concept. For instance, in the question, “What did you buy?”, the answer would be a noun or noun phrase, such as “a book,” “some groceries,” or “that new gadget.” Here, “what” serves as a placeholder for the unknown object of the verb “buy.”
Similarly, “what” can function as the subject of an interrogative sentence. Consider the question, “What is the problem?” The expected answer would be a noun or noun phrase that defines the issue, like “a software bug,” “a communication breakdown,” or “an unexpected delay.” In this context, “what” represents the unknown subject that the predicate “is the problem” describes.
Prepositional Objects
“What” also frequently appears as the object of a preposition, further refining the scope of the question. Phrases like “To what end are we pursuing this?” or “With what are you preparing the meal?” illustrate this usage. The prepositions “to” and “with” narrow the focus, asking about the purpose or the instrument, respectively. The answer will still be a noun or noun phrase that completes the prepositional phrase, providing the specific information requested.
Complementing Verbs
In sentences with linking verbs, “what” can act as a subject complement, asking for the identity or nature of something. “What is that noise?” seeks an identification of the sound. “What seems to be the issue?” probes for a description of the problem. In these cases, “what” is intrinsically linked to the subject through the linking verb, and the answer serves to define or describe that subject.
The Relative Pronoun: Connecting Clauses
Beyond its interrogative function, “what” also possesses the ability to act as a relative pronoun. In this role, it introduces a subordinate clause that functions as a noun, often referring to an unspecified antecedent. This makes “what” a particularly flexible word, capable of both asking and describing.
The “Thing Which” Function

The most common way “what” functions as a relative pronoun is in a way that is equivalent to “the thing which” or “that which.” This allows for the creation of noun clauses that can be subjects, objects, or complements within a larger sentence. For example, “What you need is a good night’s sleep.” Here, “What you need” is a noun clause acting as the subject of the sentence, and “what” refers implicitly to “the thing” that is needed.
Consider another example: “She explained what had happened.” In this instance, “what had happened” is a noun clause functioning as the direct object of the verb “explained.” “What” here refers to “the thing” that happened. This usage is crucial for conveying complex ideas and relationships, allowing writers to express nuanced meanings without explicitly stating the antecedent.
Combining Interrogative and Relative Roles
Interestingly, the relative pronoun “what” can sometimes retain a hint of its interrogative nature. When it introduces a clause that describes something with an implied question, it can create a subtle but distinct effect. For example, “I don’t understand what you mean.” The clause “what you mean” functions as a noun clause, the object of “understand.” However, “what” still inherently prompts a consideration of the specific content of the meaning, much like a direct question. This blending of functions adds a layer of sophistication to the language.
Adjectival and Adverbial Uses: Modifying and Describing
While less common than its pronominal roles, “what” can also function adjectivally and, in certain contexts, adverbially, adding further dimensions to its grammatical versatility. These usages are often tied to expressing surprise, emphasis, or a degree of intensity.
The Adjectival Role: Emphasizing Quantity or Quality
When “what” is used adjectivally, it typically precedes a noun and functions as a determiner, similar to “which” or “how much/many.” This usage is often exclamatory, conveying a strong emotion such as surprise, admiration, or dismay. For example, “What a surprise!” or “What a beautiful day!” Here, “what” is not asking a question but rather intensifying the noun that follows, emphasizing its remarkable quality.
In these exclamatory contexts, “what” functions to quantify or qualify the noun in a superlative sense. It doesn’t seek a specific answer but rather expresses an extreme degree of the noun’s quality. It’s important to distinguish this from a true interrogative use. The sentence structure and intonation (in spoken language) are key indicators.
The Adverbial Role: Describing Manner or Extent
While less frequent and sometimes debated by grammarians, “what” can sometimes be considered to function adverbially when it modifies an adjective or an adverb, often in exclamatory phrases. Consider the phrase “What good is it?” In this construction, “what” could be interpreted as modifying “good,” asking about the extent or degree of its goodness. It implies “how much” or “to what extent” good it is.
Another instance might be found in phrases like “What more do you want?” Here, “what” could be seen as modifying “more,” asking about the specific quantity or nature of the additional item desired. These adverbial-like functions of “what” are typically embedded within idiomatic expressions or exclamatory sentences, contributing to their forceful and expressive nature. They are less about direct information retrieval and more about conveying a heightened sense of inquiry or emphasis.

Conclusion: The Enduring Flexibility of “What”
The exploration of “how what part of speech” reveals a word of remarkable linguistic agility. From its primary role as an interrogative pronoun, seeking precise information, to its capacity as a relative pronoun, weaving together clauses, and its less frequent but impactful adjectival and adverbial functions, “what” consistently demonstrates its power to shape meaning. Its ability to function across different grammatical categories makes it an indispensable tool for constructing questions, connecting ideas, and expressing a wide spectrum of human thought and emotion. Understanding these diverse roles is not merely an academic exercise; it is fundamental to mastering the art of clear, precise, and engaging communication in the English language. The seemingly simple word “what” stands as a testament to the intricate and beautiful complexity of grammar.
