Italian speakers are often confused by the different uses of "any" and its different meanings.
Any is usually defined as being an adjective, an adverb, a pronoun, a determiner and until today I was unaware of a further subclass: a numeral
Many words of different parts of speech indicate number or quantity.
Quantifiers do not enumerate, or designate a specific number, but give
another, often less specific, indication of amount. Examples are words
such as every, most, least, some, etc.
Hence, "any" has a similar meaning to "a" and is normally used with uncountable and plural nouns.
- (a) Do you have any books? (plural noun)
(b) I haven't got any books.
- (a) Do you have a book? (singular noun)
(b) I haven't got a book
- (a) Do you need any information? (uncountable noun)
(b) I haven't got any information.
- (a) *Do you need a information? NO
(b) *I haven't got a information. NO
Examples and explanations taken (and adapted) from Practical English Usage by Michael Swan:
"Any" meanings and uses
It doesn't matter which
- It's my treat. Choose any dress you like. [Choose a/one dress]
- Take any card. [Take a/one card]
- Any book on grammar will tell you how to use "any". [Any one book = every book on grammar]
In questions and negative sentences "any" can be used with comparatives, with "different" and in the expressions any/good, any/use, and any/point.
- Is she any better?
- I can't walk any further
- You don't look any different now than ten years ago.
- Is there any point in carrying on?
- Was the film any good?
In sentences with negative adverbs such as never, hardly and rarely
- He never has any spare time
- She hardly eats anything
- They rarely visit anyone
As a result the OP's phrases:
It can be found in any book
It can be said in any language
This can be understood by anyone (i.e. any person)
mean it doesn't matter which book/language/person, because every book/language/person has this quality or ability.