Would you tell Jenny?

> I interpret this as a polite request to ask Jenny to do something if she would like to. Someone is asking Jenny a favor.

Will you tell Jenny?

> I interpret this as a indirect request that someone hope Jenny can do something and Jenny might not have too much choice ( of course, she can turn down any request as she doesn't feel like doing.)

Or maybe I was wrong. Both sentences don't make much difference. Only that 'would' is more polite than 'will'.

How about this?

Would you please help?

Will you help?

I look forward to your answer.
I'd interpert "would" as being a polite request and "will" as being a direct question. That's generally how those terms would be used. However, the nature of "would" is that it is conditional on something, so it really expects some completion to the sentence, ie "Would you please help if.....". Grammatically that is what would be expected, but it isn't necessarily used in this fashion, especially in every day speech.
Dialog A
Migo: The outing has been put off. Will/Would you tell Jenny?
Pastel: Yeah, sure.

Dialog B
Pastel: Hi, teacher, will and would get me confused! If you don't explain to me, my head is going to explode! Would/Will you help me please?

Migo: Here you are. $^%&&*.

According to what you've said <> Which is more commom in daily conversation? Or feel free to cross out the sentecne I've wrote. Emotion: smile

Many thanks!
Students: Are you brave enough to let our tutors analyse your pronunciation?
Dialog A: I'd pick would as being the better answer. In this case it's a polite request, so would is more appropriate. You could say will if you wanted to, and I don't think it would really make a difference.

Dialog B: Again I'd go with would simply on account of it implying more of a polite request. Will would be equally appropriate however, it just sets a slightly different tone.

I think you'll find that both are equally common in daily conversation and you can use both interchangably without running into any difficulties. There will be the odd situation in which case only one or the other would be apropriate, but it depends on the meaning you're trying to convey.

The key point you should look at is: Is the question conditional on anything? If the answer is yes, then you should go with would, if the answer is no then you should go with will. Chosing the "wrong" one is unlikely to be of any tragic consequence.
In your dialogues A and B, the ideal word is 'would'. Because it should be in the form of some polite request.

People could speak what they want; however, people who know English grammar will use the word would in the given context.
Also, if you're dealing with would/will in the context of something other than a question, ie as a suggestion, if you are in doubt chose would. Would in the context of a suggestion or statement is more polite and less authoratative. However, don't take this to mean that will is impolite because it isn't, it just has a more brisk tone to it. If you're talking to someone of a higher rank, would is always the best option. If you're talking to someone of a lower rank then either is a viable option, and it just depends on how you want to speak with them.
Site Hint: Check out our list of pronunciation videos.
Thank you. Andrei
Migo, thanks for relieving my headache. I'm not going to explode![F]
Thank you
Teachers: We supply a list of EFL job vacancies