Valency and Lexical Complement Patterns

A predicate's valency is the set of participants and complement types that its meaning licenses. Ăn can take what is eaten; đến takes an arriver and commonly a destination; ở relates a person or thing to a location; nói can introduce an interlocutor with với and a topic with về. These patterns belong to the Vietnamese predicate, not to the nearest English translation.

Vietnamese makes valency especially visible because predicates do not conjugate. The form thấy remains thấy whether the subject is “I” or “they” and whether the seeing happened yesterday or is happening now, but what follows it can be a perceived noun phrase, a participant plus another predicate, or a content clause. Morphology is simple; complement grammar is rich.

Learn a frame, not an isolated translation

In the first clause, cơm fills the food object slot. In the second, the object is omitted because the activity “eat/have a meal” is enough; ở công ty is a location, not the thing eaten. The lexical frame remains available even when a participant is not pronounced.

Direct objects do not match English prepositions

English and Vietnamese frequently package the same relationship differently. Several Vietnamese predicates take a noun phrase directly where English uses a preposition.

Chờ, tìm, and nghe take xe buýt, chìa khóa, and nhạc directly. Adding cho because English says for, or đến because English says to, produces the wrong frame.

The reverse also happens: Vietnamese may require a relational word that an English learner is tempted to omit.

Phụ thuộc vào and đồng ý với should be learned as units. The English preposition sometimes happens to resemble the Vietnamese relationship, but translation is not a reliable derivation rule.

Destinations, locations, and existence have different frames

Movement đến, location ở, and existential có organize their participants differently.

Đến + destination encodes movement to an endpoint. Ở + location describes location, residence, or staying. Location-first Ở đây có Wi-Fi introduces something present, whereas possessor-first Tôi có một câu hỏi relates the possessor to what they have. English uses at, stay, and there is/have; Vietnamese chooses among lexical constructions.

The direction word đi also combines directly with destinations and activities: đi Hà Nội “go to Hanoi,” đi làm “go to work,” đi ăn “go eat.” Do not automatically insert đến before every destination or purpose.

Noun, predicate, and clause complements

A complement is not always a noun object. Vietnamese predicates can select another predicate phrase or a whole proposition.

After muốn, the desired action đi sớm follows without an infinitive marker equivalent to English to. Giúp + person + predicate presents who receives help and what they are helped to do. Bảo + person + predicate presents an addressee and the requested or commanded action. The downstream predicate remains uninflected.

Knowledge and speech predicates may take content:

Rằng explicitly introduces reported content and is frequent in writing and careful speech (formal), but it is often omitted after common predicates when the clause boundary is clear: Tôi biết chị ấy đang ở Hà Nội. Its omission does not turn chị ấy into an ordinary direct object equivalent to a thing that is known; the whole following proposition is the content.

Perception and causation build layered predicates

Thấy can take a perceived entity alone or an entity followed by a predicate describing it.

In the second example, chị Lan is perceived and also understood as the subject of đi vào phòng họp. English may use an infinitive (saw Lan enter) or an -ing form; Vietnamese simply sequences the participant and predicate according to the thấy + participant + predicate frame.

Làm can be an ordinary action predicate or part of a causative pattern:

Here tin đó causes a result in tôi, and thấy nhẹ nhõm hơn names the experience. A more explicit causative link can use làm cho: Tiếng ồn làm cho em bé thức giấc “The noise made the baby wake up.” The choice between làm and làm cho depends on the construction and style; it is not an agreement change.

Valency alternations are lexical, not automatic

Some predicates permit related frames with the same form:

In the first, cửa is the entity undergoing the change. In the second, tôi is an agent and cửa is the affected object. Mở supports both frames.

Do not generalize this alternation to every one-participant predicate. Ngủ “sleep” does not ordinarily acquire the causative meaning “put someone to sleep” just by adding an object. Vietnamese instead chooses a lexical or causative construction such as ru em bé ngủ “lull the baby to sleep” or làm cho em bé ngủ “make the baby sleep.” Which alternations are possible is part of knowing the predicate.

Property and nominal complements are not interchangeable

Property predicates stand directly after their subject, while ordinary nominal classification uses là.

Lạnh and ấm predicate properties without là. Là giáo viên identifies a category. Làm biên tập viên uses làm with a role complement and emphasizes working in that role. These complements should not all be labeled “objects” merely because they follow a predicate-like word. The finer contrast involving classification là belongs on Là for Classification and Identification.

A natural exchange with several frames

The dialogue uses đến + destination, ở + location, direct chờ + participant/event, bảo + person + predicate, nói với + interlocutor + về + topic, and cho + recipient + xem. Natural Vietnamese emerges from these learned frames, not from translating every English preposition separately.

Quick decision aid

1. Does the predicate take an affected, perceived, consumed, or awaited thing directly? Learn that noun-object frame.
2. Does it select a destination or location? Distinguish đến + destination from ở + location.
3. Is a relational word part of the frame? Keep với in nói/đồng ý với and vào in phụ thuộc vào.
4. Does another action follow? Check whether the frame is muốn + predicate, giúp/bảo + person + predicate, or another lexical pattern.
5. Is the complement a proposition? Rằng may mark it explicitly, especially in formal writing, but is not always required.
6. Can the same form appear in one- and two-participant frames? Verify the alternation word by word; never assume it is productive.
7. Is the following phrase identity, role, property, place, or a direct object? Give it the analysis licensed by the predicate, not by position alone.

Common Mistakes

1. Importing English for after chờ.

Everyday chờ takes the awaited participant directly.

2. Importing English to after nghe.

Nghe + sound/content is the lexical frame.

3. Omitting a required relational word.

Store phụ thuộc vào as a unit.

4. Adding là before a property.

Use là for the appropriate nominal identification frame, not as a universal linker.

5. Assuming an English transitive verb has the same valency.

The ordinary pattern here is giải thích + content + cho + recipient.

Key Takeaways

Valency is lexical knowledge: each Vietnamese predicate licenses particular participants and complement types. Direct objects, destination and location phrases, relational phrases, following predicates, and content clauses cannot be predicted reliably from English. Learn invariant predicate forms together with natural frames, and treat alternations such as Cửa mở / Tôi mở cửa as properties of individual predicates rather than a universal transitivity rule.