By Who or By Whom: Which One is Correct? [English]

The English language presents countless grammatical puzzles that trip up even seasoned writers. Among these challenges, the choice between "by who" and "by whom" stands as one of the most persistent sources of confusion. This distinction matters because it reflects your understanding of grammatical relationships and can significantly impact how others perceive your communication skills.

Understanding this grammatical choice requires examining the fundamental roles these words play in sentence structure. The confusion stems from the fact that both phrases appear to serve similar functions, yet only one follows standard grammatical rules. This distinction becomes critical in professional writing, academic discourse, and formal communication where precision matters.

Understanding "Who": Formation and Grammatical Function

"Who" functions as a subjective pronoun in English grammar. This means it serves as the subject of a sentence or clause—the entity performing the action. The word derives from Old English "hwa," maintaining its role as an interrogative and relative pronoun throughout centuries of linguistic evolution.

When "who" appears in a sentence, it identifies the person or entity carrying out the verb's action. Consider this structure: "Who completed the project?" Here, "who" seeks to identify the subject responsible for completing the action. The grammatical relationship remains clear—"who" connects directly to the verb as its subject.

In relative clauses, "who" introduces information about a person while maintaining its subjective function. For example: "The consultant who designed the strategy received recognition." The pronoun "who" refers back to "consultant" and serves as the subject of the verb "designed" within the relative clause.

The formation of questions with "who" follows predictable patterns. When seeking the subject of an action, "who" naturally occupies the beginning position: "Who will attend the meeting?" This structure mirrors declarative sentences where the subject precedes the verb, making "who" the appropriate choice for subjective functions.

Understanding "Whom": Formation and Grammatical Function

"Whom" serves as the objective form of "who," functioning as the object of verbs or prepositions. This distinction carries significant grammatical weight, though modern usage has somewhat relaxed these traditional boundaries. The word evolved from Old English "hwam," the dative and accusative form of "hwa."

The objective case means "whom" receives the action of a verb or follows a preposition. When a sentence requires an object—someone or something receiving the action—"whom" provides the grammatically correct choice. This function becomes clearer when examining sentence structure and identifying which element receives the action versus which element performs it.

Prepositions create the most straightforward applications for "whom." Words like "to," "for," "with," "by," and "from" require objective pronouns to complete their meaning. The phrase "by whom" exemplifies this relationship, where the preposition "by" demands an objective pronoun to follow grammatical convention.

In formal writing, "whom" maintains its traditional role despite shifting casual usage patterns. Academic writing, legal documents, and professional correspondence still adhere to these distinctions. Understanding when to use "whom" demonstrates mastery of formal English grammar and enhances credibility in professional contexts.

Grammar Study: The Prepositional Relationship

The combination "by whom" represents a prepositional phrase where "by" functions as the preposition and "whom" serves as its object. This grammatical relationship follows established rules governing prepositions and their objects in English syntax.

Prepositions establish relationships between different sentence elements, indicating direction, location, time, or method. The preposition "by" typically indicates agency—identifying who or what performs an action. When this preposition requires a pronoun object, grammatical convention demands the objective form "whom" rather than the subjective "who."

This prepositional relationship becomes evident when transforming questions into statements. "By whom was this decision made?" transforms into "This decision was made by him/her." The pronoun "him" or "her" clearly demonstrates the objective case, supporting the use of "whom" in the original question.

The grammatical principle extends beyond questions to relative clauses and other constructions. "The person by whom the report was written" maintains the same prepositional relationship, with "by" requiring its object to appear in the objective case. This consistency across different sentence types reinforces the grammatical rule.

Common Confusions and Similarities

The confusion between "by who" and "by whom" stems from several linguistic factors that create uncertainty for speakers and writers. Modern English has simplified many grammatical distinctions, leading to reduced emphasis on case differences in casual speech. This evolution creates tension between traditional grammar rules and contemporary usage patterns.

Spoken English often blurs these distinctions because the difference between subjective and objective pronouns has diminished in everyday conversation. Many speakers use "who" in all contexts, relying on word order and context to convey meaning rather than grammatical case. This shift influences written language, where informal styles mirror spoken patterns.

The similarity in sound and spelling between "who" and "whom" contributes to confusion. Unlike pronouns such as "I/me" or "he/him," where the difference is more pronounced, "who" and "whom" differ by only one letter. This minimal distinction makes errors more likely, especially in rapid speech or casual writing.

Another source of confusion arises from the declining use of "whom" in contemporary English. Many style guides now acknowledge that "whom" sounds formal or archaic in certain contexts, leading to uncertainty about when its use is appropriate. This linguistic evolution creates a gray area where traditional rules conflict with modern usage preferences.

Key Differences and Correct Usage

The fundamental difference between "by who" and "by whom" lies in grammatical case requirements. "By whom" follows standard grammar rules because prepositions require objective pronouns as their objects. "By who" violates this rule by placing a subjective pronoun after a preposition, creating a grammatical error in formal English.

Understanding this difference requires recognizing the grammatical function each word serves. "Who" identifies the subject performing an action, while "whom" identifies the object receiving an action or following a preposition. This functional distinction determines correct usage regardless of whether the construction appears in questions, statements, or relative clauses.

The preposition "by" specifically indicates agency or method, requiring an objective pronoun to complete its meaning. This requirement makes "by whom" the only grammatically correct option when formal grammar rules apply. The construction "by who" cannot satisfy this grammatical relationship because "who" cannot function as a prepositional object.

Professional and academic writing contexts typically demand adherence to these traditional grammar rules. Legal documents, scholarly articles, business correspondence, and formal presentations benefit from precise grammatical usage. In these contexts, "by whom" demonstrates grammatical competence and attention to detail.

Practical Applications in Professional Writing

Professional communication requires careful attention to grammatical precision, making the "by whom" versus "by who" distinction particularly relevant. Email correspondence, reports, presentations, and formal documents all benefit from accurate grammar usage. The choice between these phrases can influence how colleagues, clients, and supervisors perceive your communication skills.

Business writing often involves questions about responsibility, authority, and decision-making processes. Phrases like "by whom was this approved?" or "determine by whom these changes were authorized" appear frequently in professional contexts. Using the correct grammatical form enhances clarity and demonstrates professionalism.

Academic writing places even greater emphasis on grammatical accuracy. Research papers, thesis documents, and scholarly articles require adherence to formal grammar rules. The phrase "by whom" appears in literature reviews, methodology sections, and citations where precise language matters. Academic institutions and publishers expect this level of grammatical sophistication.

Legal writing represents perhaps the most demanding context for grammatical precision. Contracts, briefs, and legal opinions require unambiguous language where grammatical errors can affect meaning and interpretation. The phrase "by whom" appears in legal documents to identify parties, witnesses, and responsible entities with complete clarity.

Modern Usage Trends and Evolving Standards

Contemporary English usage shows increasing flexibility regarding "who" and "whom" distinctions, particularly in informal contexts. Many style guides now acknowledge that strict adherence to traditional case rules may sound overly formal or pedantic in casual communication. This evolution reflects broader changes in how English speakers approach grammatical complexity.

Digital communication platforms have accelerated these changes by prioritizing speed and accessibility over grammatical precision. Social media, text messaging, and informal email often use "who" in all contexts, focusing on communication efficiency rather than grammatical accuracy. These platforms influence broader usage patterns and shape evolving language norms.

However, the relaxation of these rules varies significantly across different communication contexts. While casual conversation may accept "by who" without confusion, formal writing contexts continue to value traditional grammatical distinctions. Understanding these contextual differences helps writers choose appropriate language for their specific audience and purpose.

Educational institutions face particular challenges in addressing these evolving standards. Grammar instruction must balance traditional rules with contemporary usage while preparing students for various communication contexts. The "by whom" versus "by who" debate exemplifies broader questions about prescriptive versus descriptive approaches to language education.

Testing Your Understanding: Practical Strategies

Developing confidence with "by who" versus "by whom" requires practical strategies for identifying correct usage. The substitution method provides a reliable approach: replace the questioned pronoun with "he/him" or "she/her" to determine the appropriate case. If "him" or "her" sounds correct, use "whom"; if "he" or "she" sounds correct, use "who."

For example, testing "By who/whom was this created?" becomes "This was created by him/her." Since "him" or "her" sounds natural, "whom" is correct. This substitution method works consistently across different sentence structures and helps internalize the grammatical relationship.

Another strategy involves identifying the preposition and its object relationship. When "by" appears before the pronoun in question, the grammatical structure requires an objective pronoun, making "whom" the appropriate choice. This pattern recognition helps develop intuitive understanding of correct usage.

Reading high-quality writing provides exposure to correct usage patterns. Professional publications, academic journals, and well-edited books demonstrate proper grammar usage in context. This exposure helps develop an ear for correct constructions and builds confidence in applying these rules.

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