Vietnamese is often erroneously considered to be a "monosyllabic" language. It is true that Vietnamese has many words that consist of only one syllable; however, most words are indeed bi-syllabic. This is largely because of the many reduplication words that appear in household vocabulary, or adjectives.
Vietnamese syntax conforms to the Subject Verb Object word order.
Although it is not usually required, past tense is indicated by adding the particle đã, present progressive tense by the particle đang, and future tense is indicated by the particle sẽ.
The topic-comment structure is an important sentence type in Vietnamese. Therefore Vietnamese has often been claimed to be a topic-prominent language (Thompson 1991). As an example the sentence "tôi đọc sách này rồi" can be transformed into the following topic prominent equivalent.
Sách này thì tôi đọc rồi.
book this (TOPICMARKER) I read already
I already read this book.
Although it is not usually required, the plural may be indicated by particles like những, các, chúng.
Vietnamese extensively uses a system of classifiers to indicate word classes of nouns. English classifiers, for example, may be (highlighted in bold) one head of cattle or three pieces of cheese. Vietnamese's system and usage of classifiers are similar to Chinese and are more variable than English. Among the most common classifiers are:
~ cái : used for most inanimate objects;
~ con: usually for animals, but can be used to describe some inanimate objects (con dao = knife, con đường = street, con vít = screw)
~ bài: used for compositions like songs, drawings, poems, essays, etc.
~ cây: used for stick-like objects (plants, guns, canes, etc.)
~ chiếc: objects that are worn or moved by people (chairs, cars, ear rings, ships, shirts, shoes)
~ tòa: buildings of authority: courts, halls, "ivory towers".
~ quả/trái: used for globular objects (the Earth, fruits)
~ quyển/cuốn: used for book-like objects (books, journals, etc.)
~ tờ: sheets and other thin objects made of paper (newspaper, paper, calendar etc.)
~ việc: an event or an ongoing process
The classifier cái has a special role in that it can extend all other classifiers, e.g. cái con, cái chiếc.
Vietnamese pronouns are more accurately forms of address. Its concept is different from that in European languages, so its forms of address do not neatly fall into the grammatical person classifications created by European grammarians. For example, the same word can be used as a first-, second-, or third-person pronoun, depending on the speaker and the audience. The sentence:
Ông đi về nhà.
Grandfather go return home.
can be translated as:
~ I (your grandfather) go home.
~ You (old man/my grandfather) go home.
~ He (the old man) goes home.
The most common forms of address are kinship terms, which might differ slightly in different regions. Most of them derived from Chinese loanwords, but have acquired the additional grammatical function of being pronouns over the years.
When addressing an audience, the speaker must carefully assess the social relationship between him/her and the audience, difference in age, and sex of the audience to choose an appropriate form of address. The following are some kinship terms of address that can be used in the second-person sense (you). They all can also be used in the first-person sense (I), but if they're not marked by (S) the usage is limited to the literal meaning:
~ Ông: grandfather, used as a term of respect for a man senior to
the speaker and who is late middle age or older
~ Bà: grandmother, used as a term of respect for a (usually married) woman senior to the speaker and who is late middle age or older
~ Cô: father's sister, used to address a younger woman or a woman as old as one's father.
~ Chú: father's younger brother, used to address a younger man or a man slightly younger than one's father.
~ Bác: father's older brother, used to address a man slightly older than one's father.
~ Anh: older brother, for a slightly older man, or for the man in a romantic relationship. (S)
~ Chị: older sister, for a slightly older woman. (S)
~ Em: younger sibling, for a slightly younger person, or for the woman in a romantic relationship. (S)
Other pronouns in use for the most part conform to the European idea of grammatical person. Some are even gender-neutral and relationship-neutral:
~ Tôi: I, (literally servant)
~ Hắn: pejorative he
~ Ông ta/Ông ấy: he (see above)
~ Bà ta/Bà ấy: she (see above)
~ Cô ta/Cô ấy: she (see above)
~ Anh ta/Anh ấy: he (see above)
~ Họ: they
~ Nó: it (also he or she, when referring to a subordinate; perhaps also pejorative)
~ Chúng ta: we (including audience)
~ Chúng tôi: formal I, we (excluding audience)
~ Chúng nó: they (pejorative)
~ Bả: colloquial, she
~ Mày: you singular (to subordinates, or extremely informal)
~ Quý vị: you (formal)
~ Bạn: friend, you
Reduplication (từ láy) is found abundantly in Vietnamese. They are formed by repeating a part of a word to form new words, altering the meaning of the original word. Its effect is to sometimes either increase or decrease the intensity of the adjective, and is often used as a literary device (like alliteration) in poetry and other compositions, as well as in everyday speech.
Examples of reduplication increasing intensity:
~ đau → đau điếng: hurt → hurt like hell
~ mạnh → mạnh mẽ: strong → very strong
~ rực → rực rỡ: flaring → blazing
Examples of reduplication decreasing intensity:
~ nhẹ → nhè nhẹ: soft → soft (less)
~ xinh → xinh xinh: pretty → cute
~ đỏ → đo đỏ: red → somewhat red
~ xanh → xanh xanh: blue/green → somewhat blue/green
Reduplication of this type, indicating diminished intensity, is also present in Mandarin Chinese.
A type of assimilation known as tonal harmony is involved in Vietnamese reduplication.