An article explaining the difference between will and going to when talking about the future.
There are a number of ways of dealing with these tricky grammar distinctions, and a lot will depend on the level and needs of the students, their learning style, your institutional demands (e.g. whether the distinction is to be tested in a forthcoming exam), and finally, your own personal theories of language learning. Here are some ideas of my own:
Will vs Going to
Ignore it completely, especially at lower levels.
The difference between will and going to (not to mention other ways of expressing futurity) is so subtle that it cannot be easily conveyed through rules or isolated examples. Moreover, often the two forms are interchangeable (I think it will rain / I think it’s going to rain) or the meaning overlaps to such an extent that there is no risk of the learner being misunderstood.
Teach some 'rules of thumb', and hope that these are sufficient to deal with the majority of instances that learners will come across. For example:
Rule of thumb 1
Going to is a kind of present tense – look at its form! – so you use it when you want to talk about a future situation that is already connected to the present, e.g. because there’s present evidence, or because a plan is already in motion:
I think it’s going to rain – I just felt a drop.
They’re going to retire to the country – they’ve already bought a little cottage.
In other cases, where there is no implicit or explicit connection to the present, use will:
The concert will be over by midnight.
I’ll light the barbecue.
Rule of thumb 2
When you’re making predictions, you can use will or going to more or less interchangeably.
I think it’s going to rain.
I think it will rain.
When you’re expressing an intention or decision, use will if you’re making the decision as you speak; use going to if you have already made the decision:
A: Can you give me a hand?
B: OK. I’ll light the barbecue.
A: Can you give me a hand?
B: No, sorry. I’m going to bath the baby.
The problem with this rule is:
a) It doesn’t always work in real life (think of what you say in a restaurant, as you sit down with your friends, and what you say to the waiter when you order):
A: What are you going to have?
B: Hmm I think I’m going to have the fish…
A: Are you ready to order?
B: Yes, I’ll have the fish…
b) It lacks 'psychological' validity. When is a decision pre-planned vs planned? I had a student once who said: 'All my decisions are pre-meditated!'
And/or Rule of Thumb 3
To talk about the future use will. This is the rule that most learners operate on. Statistically, it is a safe bet. Will is much more common than going to in all meanings (prediction and intention) and all registers (conversation and writing). In fact, will is the most common modal verb in English. Future meaning is more often expressed by will than any other form. So, when in doubt, use will. (These facts come from the Longman Grammar of Spoken and Written English which is based on a 40-million word corpus of spoken and written text).
And/or Rule of Thumb 4
Use will in writing and going to in speaking. While this is not as reliable as Rule of Thumb 3, it is supported by corpus evidence. Going to is most common in conversation (although never as common as will), and more common in American than British conversation. It is relatively infrequent in written English.
Introduce both forms in their typical contexts of use, and associate them with specific functions and expressions. Avoid trying to contrast them.
This is the approach that was taken traditionally. You taught going to in the context of planning, and you presented it through dialogues where this context was clear and where it was associated with certain expressions:
What are you going to do this summer?
We’re going to spend a few days at the beach and then I’m going to go* to Dublin to study English for a month.
*Ignore books that tell you that going to go is to be avoided. You’ll find hundreds of examples in any corpus.
Likewise, teach will initially in the context of offers and requests: I’ll carry the bags, if you like. Will you get the phone, please? I’m in the bath. etc. Later, re-introduce it in the contexts of predictions, e.g. along with if/when: If you leave now, you’ll just make it.
This way the forms become 'attached' to particular functions and particular expressions, allowing the learner a foothold into their 'deeper' meanings. Through subsequent trial-and-error, plus lots of exposure, these proto-rules will re-shape themselves naturally. Forcing the issue by attempting to contrast them prematurely will result in forced errors, according to Thornbury’s First Law of Grammar: 'If something can go wrong, it will'.
Ignore Thornbury’s First Law, and attempt a contrast, e.g. in some mini-situation, such as:
(Substitute whatever lexical items you prefer).
A: I’m going to the shops.
B: What are you going to get?
A: Coffee. And I’m going to get more biscuits for the kids.
B: We’re out of milk.
A: OK, I’ll get some.
Ask learners to decide on the reasons underlying the choice of underlined items. They will probably come up with the usual 'default' rules about certainty and proximity: 'You use X structure if you are more certain', or 'You use Y structure because it is nearer'. Demonstrate that this is not the case. Establish the difference between pre-meditated vs. spontaneous decisions (see above); follow up with some de-contextualized gapped sentences. Then role-play the preparations for the end-of-course party. Start counting the mistakes. When you get to 100, move on to Option 5.
Option 5 (Deep-end approach)
Set up situations in which learners have to use future forms: e.g. have a chat about the forthcoming holidays/weekend/elections/Olympic Games etc etc. Or try a Community Language Learning activity (see Uncovering Grammar, p. 70), and set a future theme.
Learners will attempt to express futurity using available means, e.g. present tense plus future time adverbial (Tomorrow I go to the cinema) or will (Next summer I will go to Rome…). Provide correction – e.g. in the form of re-casting (see Uncovering Grammar, p. 34) – and keep a note, if possible, of some of these instances of learner talk vs. user talk. Put these on the board or a transparency and allow students time to study them, and attempt to work out some rules/tendencies. Repeat the activity, encouraging them to incorporate the 'user forms' into their production.
During this type activity, it will not always be clear whether the student is using the forms in their standard way. For example, if the student says 'Tomorrow I’ll go to the cinema', in the absence of any other information, how are you to know if this is a spontaneous or a planned decision? By asking, you can clarify your own doubts, while at the same time, help drive home the difference between will and going to.
Student: Tomorrow I’ll go to the cinema.
Teacher: You mean, you’ve just decided?
Student: No, I always go to the cinema on Friday.
Teacher: Ah, so you’re going to go this Friday, too?
(For more on this kind of 'nudging' correction, see Uncovering Grammar, pp. 32- 35.)