nó

1. For Animals and Objects (Neutral)
Nó is the standard word for 'it'. It is completely neutral and used in everyday speech.

2. For Humans (Casual, Offensive, or Literary)
When meaning 'he' or 'she', nó is strictly casual in spoken language. You can safely use it for:

• Small children
• Much younger relatives (like a younger sibling)
• Extremely close, same-age friends

Additionally, native speakers use nó in a deliberately derogatory way to refer to adults they actively dislike, hold in contempt, or are angry at (such as a criminal or an enemy). In highly informal speech, nó is sometimes used to refer to a generic, hypothetical third party (similar to a generic 'they' or 'the other guy' in English), though người ta is the standard and most frequent equivalent for 'they' or 'people' in general.

Literary Note: In Vietnamese literature and fiction, nó is frequently used as a standard, neutral third-person narrative pronoun for a young protagonist or character, losing its derogatory or overly casual spoken baggage.

Warning: Never use nó to refer to a teacher, an older person, or a respected adult in real life. Doing so sounds incredibly rude and arrogant. Instead, use a kinship term plus ấy (like anh ấy or chị ấy).

3. Common Patterns

• Plural: Add chúng, bọn, or tụi before it to mean 'they' (chúng nó, bọn nó, or tụi nó - very common in Southern Vietnamese). Note: You cannot use the plural marker các with nó (các nó is ungrammatical). These plural forms carry the exact same casual or disrespectful restrictions as nó. To say 'they' politely when referring to adults, use họ or a plural marker + kinship term + ấy (like các anh ấy).
• Possession: Use của to mean 'its/his/hers' (của nó).
• Reflexive/Emphatic: Use chính nó to mean 'that exact one/thing'. Use tự nó or bản thân nó to mean 'by itself' or 'on its own'.
• Topic-Comment & Emphasis: Vietnamese speakers often state a topic, then use nó to refer back to it for subjects ('My cat, it is sleeping'). However, for inanimate objects, using nó as a direct object is highly unnatural 'translationese'. The standard rule is to drop the inanimate object pronoun entirely when the context is clear (e.g., 'That book, I read it already' is simply Quyển truyện đó, tôi đọc rồi). It is also frequently used as an emphatic or dummy filler in spoken Vietnamese (e.g., 'My personality is just like that' - Cái tính tôi nó thế).
• Dropping the Subject: Vietnamese is a pro-drop language, meaning subject omission is very common. Nó is frequently dropped entirely in the subject position when the context is clear (e.g., 'Where is the dog? It is sleeping.' - Con chó đâu rồi? Đang ngủ.).

4. Dummy Subjects
Unlike English, Vietnamese does not strictly require a "dummy" subject 'it' for time or weather (e.g., you can just say 5 giờ for "It is 5 o'clock" or Trời mưa for "It is raining"). However, in spoken Vietnamese, nó is frequently used as an optional dummy subject for weather verbs, existential constructions, and general statements (e.g., Nó mưa bây giờ đấy or Nó mưa tầm trưa). You might also hear native speakers say trời nó mưa, where nó acts as an emphatic topic-comment filler referring back to trời (the sky).