"Is this your..." in English

 There are several ways to say "Is this your..." in English, depending on the context and how polite you want to be. Here are some common options:

Most Common & General:

• Is this your ...? This is the most straightforward and versatile option. It works in most situations. For example: "Is this your book?"

More Polite:

• Excuse me, is this your ...? Adding "Excuse me" makes the question more polite, especially if you're approaching someone you don't know. For example: "Excuse me, is this your umbrella?"
• I'm sorry, is this your ...? Similar to "Excuse me," this is a polite way to get someone's attention before asking. For example: "I'm sorry, is this your bag?"

Less Formal/Casual:

• Is this yours? This is a shorter and more casual way to ask if something belongs to someone. It's suitable for friends, family, or in situations where you're already interacting with the person. For example: "Is this yours?" (if you're holding a pen)
• This your ...? This is a very informal and sometimes grammatically incorrect way to ask, but it's common in casual conversation, especially in spoken English. For example: "This your phone?" (However, "Is this your phone?" is always preferable.)

If you're unsure if the item is lost:

• Is this your ...? I think you might have dropped it. This is a considerate way to return a lost item. For example: "Is this your wallet? I think you might have dropped it."

Which one should you use?

• "Is this your ...?" is the safest and most common option for most situations.
• Use "Excuse me" or "I'm sorry" to be more polite, especially with strangers.
• "Is this yours?" is fine for casual situations.
• Avoid "This your ...?" in formal writing or when speaking to people you don't know well.

No matter which phrase you choose, a friendly tone and a smile will make your question more welcoming.