Quick Answer
While both words often appear in similar positions, đều emphasizes that every member of a group shares a specific quality or action (meaning 'all' or 'both'), whereas cũng indicates that a subject shares a quality or action with another entity mentioned previously (meaning 'also' or 'too').
Comparison Table
| Feature | đều (All / Both) | cũng (Also / Too) |
|---|---|---|
| Hán-Việt | 調 (Điệu/Điều) - Harmony, Equality | Pure Vietnamese |
| Core Meaning | Distributive: Applied to every member of a group. | Additive: Adding a new subject or action to a previous one. |
| Subject Requirement | Requires a plural subject (two or more). | Can be used with singular or plural subjects. |
| Focus | Focuses on the totality/consistency of the group. | Focuses on similarity or addition. |
| Example | Chúng tôi đều là sinh viên. (We are all students.) | Tôi cũng là sinh viên. (I also am a student.) |
Detailed Explanation
1. When to use 'đều'
Use đều when you want to highlight that a group of people or things are the same in some way. It functions as a distributive marker. In many cases, it translates to 'all' or 'both', but its primary job is to show that the predicate applies equally to every part of the subject. It is almost always preceded by a plural noun or a list of items.
2. When to use 'cũng'
Use cũng to indicate that a situation is the same as a previous one. It links a new piece of information to what has already been established. If your friend orders a coffee and you want one too, you use cũng. It does not require a plural subject because the 'other' part of the comparison is implied or mentioned in the previous sentence.
3. The combination: 'cũng đều'
In B1 level Vietnamese, you will encounter cũng đều. This is used when a whole group (đều) shares a characteristic that someone else or another group already has (cũng). For example: 'My brother is tall, and my sisters cũng đều (also all) are tall.'
Example Pairs
Hai người họ đều thích ăn phở.
Both of them like eating pho. (Focus on the pair together)
Anh ấy cũng thích ăn phở.
He also likes eating pho. (He likes it just like someone else does)
Các bài tập này đều khó.
All of these exercises are difficult. (Every single one of them)
Bài tập này cũng khó.
This exercise is also difficult. (Adding to a previous difficult one)
Sáng nào tôi cũng uống trà.
Every morning I drink tea. (Here 'cũng' works with 'nào' to mean 'every')
Sáng nay chúng tôi đều uống trà.
This morning we all drank tea.
Bố mẹ tôi đều là giáo viên.
Both my parents are teachers.
Bố tôi là giáo viên, mẹ tôi cũng là giáo viên.
My father is a teacher, my mother is also a teacher.
Common Patterns
Tất cả + Subject + đều + Verb/Adj: This is the most standard way to say 'All of...'.
Ai cũng... / Cái gì cũng...: These are fixed expressions meaning 'Everyone...' and 'Everything...'. In these cases, cũng is required regardless of the 'also' meaning.
Vừa [A] vừa [B] đều...: Used when listing two or more items that share a trait. Example: 'Cam và táo đều ngon' (Oranges and apples are both delicious).
Common Mistakes
Mistake 1 — Using 'cũng' for collective totality
Learners often use 'cũng' when they want to say 'all' just because they see multiple people.
❌ Gia đình tôi cũng thích đi du lịch.
✅ Gia đình tôi đều thích đi du lịch.
If you use 'cũng', it implies your family likes traveling just like someone else's family. If you want to say everyone in your family likes it, use 'đều'.
Mistake 2 — Incorrect word order with 'không'
When negating, 'đều' and 'cũng' must come before 'không'.
❌ Chúng tôi không đều đi làm hôm nay.
✅ Chúng tôi đều không đi làm hôm nay.
'Đều không' means 'None of us', whereas 'không đều' (rarely used this way) would imply 'not consistently'.
Mistake 3 — Using 'đều' with a singular subject
You cannot use 'đều' if the subject is only one person or thing.
❌ Tôi đều đi học bằng xe máy.
✅ Tôi cũng đi học bằng xe máy.
'Đều' requires a plural subject or a repeated action over time. For a single person's action in relation to another, use 'cũng'.
Quick Quiz
Fill in the blank with đều or cũng:
- Lan thích xem phim Hàn Quốc, Mai _____ thích xem phim Hàn Quốc.
Hint: Mai shares the same hobby as Lan.
Answer
Correct answer: cũng. Lan thích xem phim Hàn Quốc, Mai cũng thích xem phim Hàn Quốc. (Lan likes Korean movies, Mai also likes Korean movies.)
- Ba anh em nhà họ _____ cao trên một mét tám.
Hint: The sentence describes a shared characteristic of all three brothers.
Answer
Correct answer: đều. Ba anh em nhà họ đều cao trên một mét tám. (The three brothers are all over 1.8 meters tall.)
- Nhân viên trong công ty tôi _____ được nghỉ ngày lễ.
Hint: This applies to the entire group of employees.
Answer
Correct answer: đều. Nhân viên trong công ty tôi đều được nghỉ ngày lễ. (Employees in my company all get the holiday off.)