What is wrong with this phrase: “A large amount of persons”? It should pop right out at you — “persons” do not come in amounts or quantities; they come as individuals. They are countable. Aggregated, they become “many,” not “much.” Reduced in number, they are “few,” not “a little.” You can refer to them as “each one” or “every one,” and the “one” should remind you that you are in a category that is countable.
What is wrong with this phrase: “A large number of wheat”? It is the reverse situation: “Wheat” is a bulk noun. It is not countable. Units of wheat are countable, such as bushels or grains, but the substance itself is without individual members. In the aggregate, it is “much wheat,” not “many wheats.” You do not say “few wheats,” but rather, “less wheat.”
It’s hard to imagine why so many persons struggle with this distinction. Perhaps it is because the adjective “some” can refer both to countable nouns (number) and uncountable nouns (amount). The trouble starts when you add to it or take something away:
- Add to “some,” and you may find you have “many” (number) or “much” (amount).
- Take away part of it, and you have “few” (number) and “a little” (amount).
- The comparative “more” is used to express an increase in both number and amount. In the superlative, “most” is used in both contexts as well.
- On the side of diminution, however, the picture changes: The comparative “less” is reserved for uncountable nouns (amount) and “fewer” is used for number. In the superlative, “least” is reserved for amount and “fewest” for number.
This is not a matter of style or preference: these words must be used in this way, or else your English is wrong. There’s no argument about it. Here is a quick summary:
|Adjective Form||Many||Few||Much||A little|
A postscript: In informal speech, it is a mannerism to say “a lot of” (or “alotta”) instead of much or many. There is no word “alot.” Try to wean yourself from it, and use “much” or “many” or some more definite quantifier. A good one is “plenty”; another is “enough.” Here are a few more quality substitutes:
abundant, adequate, ample, complete, considerable, copious, countless, endless, galore, generous, heaps, immeasurable, lavish, loads, plenteous, plentiful, prodigious, profuse, sizable, substantial, sufficient, voluminous.
Put “a lot of” in the same category as “kind of”: fallback phrases used by habit, to avoid going to the trouble of figuring out what you really think and then expressing it.