Comma to resolve ambiguity with relative clause

Question

Does the below sentence make sens from the grammatical point of view ?

What you think is important, is very important, is extremly important.

• the comma "," is as a vehicle to determine the scope of subject

Answer 1

What you think is important, is very important, is extremly important.

• There is no nesting of relative clauses here. There is only one relative clause, and it is not an ordinary bound relative clause acting as a modifier but a free (or fused) relative clause acting as subject of the sentence.

• The sentence does make sense. Its problem is that it makes too much sense: it can be understood in two different ways, depending on the role of the first is important: is that a predicate on the subject or a constituent of the subject, a complement on think?

  1. If the free relative clause is What you think, meaning “your thought, your opinion”, then the sentence has (as CopperKettle understands it) three predicates, linked without conjunctions (this is a fairly common rhetorical device called asyndeton):

     [What you think] is important, 
             (AND IT) is very important, 
             (AND IT) is extremely important.  
     

     We would understand this to mean

     Your opinion is important; not only that, it is very important; indeed it is extremely important.

  2. But the free relative clause may be What you think is important, meaning “the matter which you think is important”. In that case there are only two predicates:

     [What you think is important] is very important, 
                          (AND IT) is extremely important.
     

     We would understand this to mean

     The matter which you think is important is in fact very important; not only that, it is extremely important.

  The comma after the first important suggests that 1 is what is meant; but it is not uncommon for writers to insert a comma in this position in sentences like 2: the comma stands for the natural pause we take in speech to mark what precedes it as a distinct syntactic unit.