Consider the following statements:
There has been a 10% decrease in the value.
The value may decrease 10% next month.
In the first sentence, decrease is a substantive while it's a verb in the second one. There's no way to distinguish their class other than by the context.
That's what I thought until a friend insisted that, in these cases, susbtantives must be written as
'decrease and verbs
de'crease, which, in over 8 years of study, I've never seen before. He just won't accept it doesn't exist. Therefore, is it even right? If not (I'm confident it's not!), how can I prove him it's not a thing?