1. Not all language tests are of the same kind.
  2. All language tests are not of the same kind

I think both the sentences mean the same thing though they are syntactically different.

What is the part of speech of not in each sentence?

I think not in the sentence 1 is an adjective as it modifies the pronoun all

And in the second sentence ,I think, not is an adverb as it modifies a verb are.

My question is:

Do the two sentences mean exactly the same? or is there any difference?

What part of speech is not in the two sentences?

  • 2
    This has zero to do with parts of speech. Suggest you visit some sites that deal with logic. Not all birds are blue. All birds are not blue.
    – Lambie
    Sep 13, 2019 at 13:29
  • @Lambie. I think it is not a matter of logic.We can identify the parts of speech.If nobody answers my question,then I will follow your advice Sep 13, 2019 at 13:32
  • 1
    I just gave you another example. It most definitely is. Also, your sentences are not really idiomatic. Normally, one would say: Not all language tests are the same. And not "of the same kind".
    – Lambie
    Sep 13, 2019 at 13:34
  • 1
    In both your examples, "not" is an adverb serving as a marker of negation. In 1. it modifies the noun phrase "all language tests", and in 2. it modifies "are".
    – BillJ
    Sep 13, 2019 at 14:03
  • 1
    Take careful note of the comments regarding the area of "logic". The English language is not completely consistent in how to express matters regarding logic. Knowing the parts of speech will help to understand this sort of sentence. But more important is understanding how English handles true/false propositions. Sep 13, 2019 at 15:05

2 Answers 2

  1. [Not all language tests] are of the same kind.

  2. All language tests [are not] of the same kind.

In both cases, "not" is an adverb serving as a marker of negation.

In 1. "not" is a marker of non-verbal negation, where it modifies the noun phrase "all language tests". In 2. "not" is a marker of verbal negation, where it modifies the auxiliary verb "are".


Both sentences mean different things, and that has to do with how logic is expressed through language.

Exchange "language tests" and "kind" with "rectangles" and "squares" to understand the difference more easily.

It is correct to say:

Not all rectangles are squares.

Rectangles where all sides are equal are squares, but rectangles without equal sides are not squares, so this statement is correct.

It is not correct to say:

All rectangles are not squares

Some rectangles may be squares as long as the rectangle has all equal sides.

In both examples, "not" is an adverb that modifies "are", but that doesn't matter much in context with understanding logic.

  • 1
    This answer makes the classic mistake of assuming that language is logical. It isn't, always. Your second example has the same structure as the proverb All that glisters is not gold, Personally I have always had difficulty with sentences of this form, but there is no doubt that people sometimes use them to mean the equivalent of your first example. (It wasn't me that downvoted you, by the way)_
    – Colin Fine
    Sep 13, 2019 at 15:42

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