He speaks so fast for me to understand.

[amiable25]

Hello, teachers. I have a question.

He speaks too fast for me to understand.
-> Is it totally wrong to say " He speaks so fast for me to understand." instead?

Thank you in advance!

 

[probus]

In a word, yes.

 

[GoesStation]

You can say He speaks so fast I can't understand him.

 

[Matthew Wai]

I would add 'that' before 'I' above.

 

[emsr2d2]

It's perfectly fine to omit "that" in BrE.

 

[Tdol]

And fine to include it.