Can one say
[color=red]
a. This instrument was brought here for cutting cheese.
b. This instrument was brought here for teaching English.
c. That person was brought here for teaching English.
?
My feeling that (a) is correct and © isn’t.
I am less sure about (b). Is the instrument used for teaching English or does the instrument teach English? I think that determines whether the sentence is acceptable or not.
Many thanks.
In my view:
a. This instrument was brought here for cutting cheese. = cutting (cheese) is what it was originally designed for
b. This instrument was brought here for teaching English. = only if you mean birch rods or another ‘instrument’ to flog those who refuse to learn English 
c. That person was brought here for teaching English. = not for being thrown\spat at during the classes. (I believe you see your © needs rephrasing: the person sounds totally inanimate or unable to manage his job).
There are better ways of expressing all the original sentences.
The only reason for using them would be if you extended the sentences to explain what they were not to be used for ( as indicated in a sense by Eugene). B needs further editing too. I would not use C as it sounds offensive to the person to refer to them in that way.
This instrument was brought here for cutting cheese, not for you to use on modelling clay.
This instrument was brought here to help me/us teach English, not to be used as a football.
That person has come to teach English.