When someone asks, "Can I borrow your car?" and you do them a solid free of charge, do you loan or lend them the car? Or are they interchangeable?

We're often taught in school that "lend" is a verb and "loan" is a noun. However, that rule was conceived by 19th century grammarians, and the use of "loan" as a verb goes back centuries, pre-dating Middle English. So in reality, you can use both "loan" and "lend". But some stubborn traditionalists may insist "lend" is the preferred word, so know your audience.

"Can I borrow your car" Where's your car? Oh I lent it to ... Lend. I'd say lend. Same thing with any help with no expectation of a return. "I'll lend you a hand" A loan is something you expect to be paid back. I'll loan you the car, but you gotta give me X,Y,Z. It's more transactional.

I would say I let them borrow my car.

Just want to throw in an example; often English language learners say: “will you borrow me (item)?” Instead of “may I borrow (item)” or “can you lend me (item)?” The first one is not correct and will lead to confusion in the native speaker until they figure out what you are asking

If you loan your car to a friend, you probably will not charge them for it. You might expect them to refill the gas tank, or maybe do an equivalent favor for you later on, but you're unlikely to charge for it. On the other hand, if you take your car into a dealership for service/repairs, you can request a "loaner" car. You may have to pay for this vehicle, even though it's called a "loan," because it's really a short-term rental car. There is no meaningful difference between loaning your car to someone and lending it to them. In both cases, you offer them something that you expect to get back later. In terms of colloquialisms... "Do someone a solid" doesn't specifically mean "lend someone something." It's much broader and can apply to most any request, like "do someone a favor." Anything that you say is "free of charge" does not need to be paid for.

Great question! In casual conversation, "lend" is usually more common when you're the one giving something temporarily like "I can lend you my car." "Loan" is technically correct too, especially in American English, but it’s used a bit more in formal or financial contexts ("a bank loan"). As for "give" and "ask," they work if the meaning is clear, like "I gave him my book to borrow" or "She asked to borrow my jacket," but they’re a little less precise.

I'd say lend. I'm British. Using "loan" as a verb is more common in American English. It sounds odd to me. I can "take out a loan", I cannot "loan something". But there are regional and generational differences. "Do them a solid" is very American too. I'd be doing them a *favour.* I don't understand your question about "give" and "ask".

You can also **give them the loan of** your car. They can also ask if they can **have the loan of** your car. Of course **borrow** is much simpler- Can I please **borrow** your car? You can **borrow** my car any time you need. And **lend** also keeps things simple- I'll **lend** you my car any time you need. -Dude, where's your car? -I **lent** it to Florence.

Loan is a noun. Lend is a verb. This is something native speakers get wrong pretty often.

Lend. You could use loan, but it would be a bit odd, loan is generally for commercial transactions involving the borrowing of money.

Loan implies that it's a long-term arrangement and that they will be paying you back with interest. Lend is less formal, shorter-term, and doesnt suggest it will be paid back with any extra.  "Let him borrow the car" is much more common, as someone else pointed out. Both lend and loan would be irregular and bizarrely formal / austere, in this context. 

I’d say lend. But I can’t put my finger on the difference.

I'm American. If I loan someone my car, I'm letting them borrow it. Borrowing is free. If I were to charge them or the use of my car I'd say I was renting it to them.

In context: may I borrow your car = will you please lend me your car? Joe loaned me his car for a week while mine was in the shop.

As a verb, "loan" means the exact same thing as "lend". It's an example of verbing a noun since originally a "loan" was just the thing that is being lent. They are now interchangeable as verbs. Never use "give" to refer to loaning someone something. That can lead to misunderstandings. I'm not sure what you mean by "ask" in your second question so, probably not.

“Lend” is better than “loan,” but I would probably use “let someone borrow.” > I lent him my car. ✅ > I let him borrow my car. ✅ (my preference) “Loan” is sometimes used this way as well, but it’s informal and probably best avoided until you’ve mastered the most natural ways to say it.