mỗi

1. The Quantifier "Each"
When used to mean "each", mỗi sits at the front of the noun phrase. For physical objects in everyday speech, it usually requires a classifier (e.g., mỗi cuốn sách). However, classifiers can be dropped in distributive contexts (e.g., mỗi bàn 5 người - 5 people per table) or formal usage. Time words (mỗi ngày) and self-classifying nouns (mỗi người) do not need an extra classifier. Unlike English, mỗi cannot stand alone as a pronoun to mean "each"; it must be followed by a noun or classifier (e.g., to say "I gave each a gift", you must say Tôi tặng mỗi người một món quà). Note that mỗi strictly means "each" (focusing on individuals), which contrasts with mọi, meaning "every" or "all" (sweeping the whole set), and từng, meaning "each in turn" or "one by one". Crucially, when a phrase with mỗi acts as the subject or a time topic for a shared action or state, the main verb is often preceded by đều (equally/all) to sound natural. However, đều is frequently omitted in distributive contexts focusing on individual differences. Note that when used, đều must go directly after the subject, not before it (e.g., Mỗi ngày tôi đều học..., not Mỗi ngày đều tôi học...).

2. The Conversational "Only"
In spoken Vietnamese, mỗi is frequently used as a modifier meaning "only" (often paired with chỉ or có). It emphasizes that a quantity or action is surprisingly limited. In this structure, mỗi sits directly before the element it restricts, which can be a noun, pronoun, or number phrase. Using it directly before a verb is colloquial speech where the verb is treated as a noun (e.g., Tôi chỉ biết mỗi ăn - I do nothing but eat / I only know how to eat). A highly common 'sandwich' structure used to mean 'only' is chỉ + [verb] + mỗi + [noun] (e.g., Tôi chỉ yêu mỗi em - I only love you). Be careful with time words: a bare mỗi before a duration or frequency noun defaults to meaning 'every' (e.g., mỗi ngày means 'every day'). However, it CAN mean 'only' directly before a duration when paired with verbs like có or được (e.g., Tôi có mỗi 2 ngày để làm việc này - I have only 2 days to do this). To unambiguously mean 'only one day' without these verbs, you should use chỉ một ngày or chỉ mỗi một ngày. Be aware that mỗi một ngày has a dual meaning: it can mean 'only one single day' (e.g., Tôi chỉ rảnh mỗi một ngày) OR it can be used emphatically to mean 'each and every single day' (e.g., Mỗi một ngày trôi qua...). However, it can be used directly before specific time points to mean 'only' (e.g., mỗi hôm nay - only today, mỗi Chủ Nhật - only Sunday). Additionally, a highly common colloquial idiom is mỗi tội, which acts as a conjunction meaning 'the only problem is...' or 'except that...' (e.g., Cái áo này đẹp, mỗi tội hơi đắt - This shirt is beautiful, the only problem is it's a bit expensive).

3. Emphatic and Distributive Patterns
You will often see mỗi một, which adds emphasis. It is the standard emphatic form for "every single" regardless of where it appears in the sentence (e.g., Tôi kiểm tra mỗi một chi tiết - I checked every single detail). However, in certain colloquial contexts, it can also mean "only a single" (e.g., Tôi tặng mỗi một món quà - I gifted only one gift). Another common structure is mỗi + [time word] + một + [adjective], which means "increasingly" over time (e.g., mỗi ngày một tốt - better each day). The highly common distributive pattern mỗi X một Y is used to express that each person or thing has their own distinct item or trait (e.g., mỗi người một ý - each person has their own opinion). Additionally, you will frequently encounter the conjunction mỗi khi (whenever / every time), which introduces a recurring event (e.g., Mỗi khi trời mưa... - Whenever it rains...).

4. Pronunciation Note
Pay attention to the ngã (~) tone. While Northern speakers distinguish it from the hỏi (?) tone, merging the two is completely standard in the Southern dialect.