... được không?

Placement: This pattern typically goes at the end of a statement or phrase to turn it into a request, suggestion, or question about ability. It can even be used entirely on its own as Được không? (Is that okay?). In writing, placing a comma right before it is optional. While it usually appears at the end, it can be followed by a person's name, title, or the respect particle.

Usage:

• Asking permission: Tôi ngồi đây được không? (May I sit here?)
• Making a request: Bạn giúp mình được không? (Can you help me?) To make a request sound softer and more polite when asking someone to do something for you, native speakers frequently pair this pattern with words like cho, giúp, giùm, or hộ placed after the main verb (e.g., Mở cửa giúp mình được không? - Can you open the door for me?). You can learn more about this in the Do It For Me pattern.
• Making a suggestion: Chúng ta đi ăn được không? (Let's go eat, is that okay?)
• Asking about ability: Bạn nói tiếng Việt được không? (Can you speak Vietnamese?) Note that for learned skills (like speaking a language, swimming, or driving), Vietnamese speakers frequently use the verb biết (to know how to) instead of được (e.g., Bạn có biết nói tiếng Việt không?).
• Requesting a change in state: You can also use this pattern with adjectives (especially comparatives) to ask for something to be different, such as Rẻ hơn được không? (Can it be cheaper?) or To hơn được không? (Can it be bigger?).

Alternative word order for ability: When asking about ability with a verb that has an object, được can be placed directly after the verb, splitting it from không (e.g., Bạn nói được tiếng Việt không?). Native speakers frequently add the standard yes/no question marker có before the verb (e.g., Bạn có nói được tiếng Việt không?). This removes the ambiguity between asking for a favor or permission and asking about physical or mental capability.

Answering: To say yes, simply reply with Được (Okay / Yes). For an enthusiastic yes, you can say Được chứ (Sure! / Of course!). To say no, reply with Không được (Not okay / No). Because a blunt Không được can sound harsh, native speakers usually soften it with an apology or a reason, such as Xin lỗi, không được rồi (Sorry, that won't work). If the question is specifically about ability (e.g., Bạn nói được tiếng Việt không?), native speakers often reply with just Không or by negating the verb directly (Không nói được), because a standalone Không được can sound like "It's not allowed" rather than "I am unable".

Adding "có thể": You will often see có thể (can / may) placed before the verb to make the request clearer, such as Tôi có thể ngồi đây được không? Even with có thể, because the question still ends with được không?, answering with Được or Không được is very common, though replying with Có or Có thể is also perfectly natural and correct.

Dropping the subject: Because Vietnamese frequently uses subject omission, pronouns are often dropped entirely in casual speech. For example, you can simply say Giúp mình được không? (Can [you] help me?).

Politeness: This pattern is neutral and great for everyday conversations. To make it highly respectful when speaking to elders or in formal situations, simply add the respect particle to the very end: ... được không ạ?

Important Note: The word được usually means "to get" or "to receive", but here it acts as a particle of possibility. Because Vietnamese has no verb conjugation, this phrase never changes form regardless of who is speaking or what the tense is.