'AS needed' what does this mean?

[duc]

Hello everyone ,

Today I read in my book a very strange sentence (maybe strange to me).Here it is:

''People invent new words,borrow words from other languages and change meaning of word as needed.''

I don't understand why we use ''as needed'' in this sentence because the subject here is ''people'' and as far as I know we have to use ''needing'' instead of ''needed'' (passive to active).I think the phrase '' as needed'' modifies ''people''.
Am I right ?

PS: (to Yankee ) Do you find my writing alright?
_________________
Don't see your shade think you are great

[Mister Micawber]

.
No, it is a passive. A fuller form would be:

People invent new words, borrow words from other languages and change meanings of words as [such changes/inventions/borrowings are] needed [by them]
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[duc]

So what is the meaning of the word ''as'' according to your new full form of the sentence?
_________________
Don't see your shade think you are great

[Mister Micawber]

.
to such a degree or extent
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[duc]

Well I don't see this meaning in my dictionary
_________________
Don't see your shade think you are great

[duc]

Can you give me a clearer explanation
_________________
Don't see your shade think you are great

[Mister Micawber]

.
4. in the manner (directed, agreed, promised, etc.): She sang as promised. He left as agreed.

6. (without antecedent) in the degree, manner, etc., of or that: She's good as gold. Do as we do.

These are a couple of the most appropriate definitions at DICTIONARY.COM.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[duc]

thank you
_________________
Don't see your shade think you are great

[duc]

Oh after I have just looked up the word ''as'' in the dictionary you tell me, I find that it is used in this sentence as an adverb but not as a conjuction.
It is so strange , isn't it?
_________________
Don't see your shade think you are great