Vietnamese, like many languages in Southeast Asia, is an analytic (and isolating) language.

Vietnamese lacks morphological markings of case, gender, number, and tense (and, as a result, has no finite/nonfinite distinction) and distinguishes them via classifier words instead.

Vietnamese is often considered to be monosyllabic as its morphemes are considered to be monosyllabic e.g. "tim" meaning "heart". However, some Vietnamese words may consist of one or more syllables, composed of monosyllabic morphemes that form together to create another word. An instance of a compound word "xe lửa" is derived from morphemes xe meaning "vehicle", lửa meaning "fire", fused to create the word xe lửa to mean "train".

There is a general tendency for words to have one or two syllables. Words with two syllables are often of Sino-Vietnamese origin. A few words are three or four syllables. A few polysyllabic words are formed from reduplicative derivation.

Additionally, a Vietnamese word may consist of a single morpheme or more than one morpheme. Polymorphemic words are either compound words or words consisting of stems plus affixes or reduplicants.

Most Vietnamese morphemes consist of only one syllable. Polysyllabic morphemes tend to be borrowings from other languages. Examples follow:

Most words are created by either compounding or reduplicative derivation. Affixation is a relatively minor derivational process.

Older styles of Vietnamese writing wrote polysyllabic words with hyphens separating the syllables, as in cào-cào "grasshopper", sinh-vật-học "biology", or cà-phê "coffee". Spelling reform proposals have suggested writing these words without spaces (for example, the above would be càocào, sinhvậthọc, càphê). However, the prevailing practice is to omit hyphens and write all words with a space between each syllable.