'I'm gonna sit right down' and 'I will always love you'

Many people in Taiwan are confused about the difference between 'will' and 'be going to'. The wrong use of 'will' is probably the most frequent mistake I hear all the time in Taiwan. Let me try to explain it to you correctly.

'be going to'= means a plan. When you are talking about your plans, you should use 'be going to'.

'I'm going to see a movie tomorrow night.' CORRECT
'I will see a movie tomorrow night.' NOT CORRECT

Listen to this song by the famous jazz composer Fats Waller. He is singing about how he is going to write himself a love letter because his girlfriend hasn't written one to him. He will pretend (make believe) his letter is from her. He is using 'be going to' because he's describing his plan to write the letter.

'will' does not mean a plan. It has many meanings, including: promise, saying goodbye, offer, request and threat, but it does not mean a plan.

I'll see you later. = saying goodbye
I'll help you with it. = offer
Will you help me? = request
I will always love you. = promise
I'll hit you! = threat

Listen to this song by Whitney Houston. She is singing about how she promises to love her man for ever. She is using 'will' because she's making a promise not describing a plan. How can you plan to love someone for ever, right?

Here are the lyrics of both songs. Listen again and follow the lyrics.

I'm gonna sit right down and write myself a letter
I'm gonna sit right down and write myself a letter
And make believe it came from you

I'm gonna write words oh so sweet
They're gonna knock me off my feet
A lotta kisses on the bottom
I'll be glad I got 'em

I'm gonna smile and say
I hope you're feeling better
I'll close with love the way you do
I'm gonna sit right down and write myself a letter
And I'm gonna make believe it came from you
Oh yeah

I will always love you
If I should stay 
I would only be in your way 
So I'll go
But I know 
I'll think of you every step of 
the way 

And I will always love you
Will always love you 
You my darling you 
Mmm-mm 

Bittersweet memories 
That is all I'm taking with me 
So good-bye 
Please don't cry 
We both know I'm not what you 
You need 

And I will always love you
Will always love you 
You my darling you 
Mmm-mm