mặc dù ... nhưng ...

This pattern is highly frequent in everyday Vietnamese. While English grammar forbids saying 'Although it rained, but I went out', Vietnamese frequently uses both halves of the pair: Mặc dù [Condition], nhưng [Result]. However, dropping nhưng is also perfectly acceptable and common.

Key Rules & Nuances:

• Although vs. Despite: Unlike English, which uses different words for clauses ('although') and noun phrases ('despite'), mặc dù can take both (e.g., mặc dù sự phản đối). However, learners should usually default to full clauses because Vietnamese adjectives act as verbs. For example, the English noun phrase 'despite the bad weather' naturally translates to a full clause in Vietnamese: mặc dù thời tiết xấu (although the weather is bad).
• Formality & Variations: Mặc dù is extremely common, but it leans slightly more formal or emphatic. You will also frequently hear tuy ... nhưng ... (which is neutral) and dù (which is the most colloquial and frequently used in everyday conversation). While dù can replace mặc dù for factual statements ('although'), it is also uniquely used for hypothetical 'even if' situations (often as cho dù ... cũng ...) where mặc dù and tuy cannot be used.
• Dropping 'mặc dù': In casual speech, native speakers very frequently drop mặc dù entirely, simply stating the condition and relying on nhưng (and often vẫn) to show the contrast.
• The role of 'vẫn': The adverb vẫn (still) is extremely common across all levels of formality to emphasize a persisting action. It pairs perfectly with negative words (vẫn không, vẫn chưa) to emphasize that an expected outcome still did not occur. As a general rule of Vietnamese syntax, vẫn typically goes before the verb or adjective, though time phrases or topic markers can sometimes intervene between the subject and vẫn.
• Shared Subject Placement & Omission: When both clauses share the same subject, the standard conjunction-first order (Mặc dù tôi mệt nhưng tôi vẫn đi làm) is extremely common. However, you can also place the subject at the very beginning of the sentence (Tôi mặc dù mệt nhưng vẫn đi làm). Furthermore, native speakers frequently use subject omission to drop the subject entirely from one of the clauses to avoid repetition (e.g., Mặc dù mệt nhưng tôi vẫn đi làm).
• Omitting or expanding 'nhưng': Native speakers commonly drop nhưng in conversation, especially when the contrast is already clear from mặc dù and vẫn. Conversely, nhưng is very frequently expanded to nhưng mà in spoken Vietnamese to soften the contrast.
• Reversing the order: If you put the result first (Result + mặc dù + Condition), you must drop nhưng entirely.
• Not for 'However': Mặc dù cannot be used as a standalone transition word at the start of a new sentence to mean 'However'. You must use tuy nhiên or mặc dù vậy instead.
• Punctuation flexibility: While a comma is standard at the end of the condition clause (right before nhưng), Vietnamese punctuation is highly flexible, and native speakers frequently omit the comma in casual writing.