Rule: Own used as a premodifier or pronoun is preceded by a possessive adjective and has emphatic meaning.
Examples of errors:
(1) Rachel should form an own opinion about Daniel.
(2) The baby soon discovers its ability to make own sounds.
(3) When I played back the recording, it was very funny to hear the own mistakes.
(4) The child should also be able to develop own ideas.
(5) Furthermore you might recognize him by his own language.
Own can be used as a premodifier, as in (l)-(5). or as a pronoun,, as in
She should form an opinion of her own.
I don't buy my cigarettes; I roll my own.
In either case own is preceded b a possessive adjective or, more rarely, by a noun with genitive -s. e.g.:
He is John's own cousin
These uses of own are to be distinguished from own used as a verb, e.g.:
He owns the house
The only exceptions to this rule occur in very rare and archaic usage to distinguish close relatives from those who are more distantly related, e.g.:
He is own cousin to the King (i.e. first cousin).
They are own sisters (i.e. not half-sisters 'or sisters-in-law).
The primary meaning of own is to make the idea of possession more emphatic, and in doing so often implies a contrast, e.g.:
He should form his own opinion.
He should form an opinion of his own.
The implied contrast (with someone else's opinion) is not present in
He should form his opinion.
although the idea of "possession" per se, the idea that the opinion is his, is the same in these sentences. Thus the semantic difference is one of emphasis. When the possessor (the person to whom the possessive adjective refers) is also the agent of an action, own can mean 'by oneself', e.g.:
She cooks her own breakfast (i.e. by herself, without anyone's help).
Own also occurs in a number of idiomatic expressions: come into one's own 'to reach maturity in some skill or quality'; for one's very own 'not to be shared with anyone'; have or get one's own back 'to get revenge'; hold one's-own 'to avoid defeat'. None of these senses fit the intended meaning in (5). This occurs in an essay describing a friend who has disappeared, for the purpose of identification. The author did not intend to emphasize or contrast the idea of the language (i.e. manner of speech) being his language as opposed to someone else's, but the idea of the language as opposed to some of his other characteristics. The correct alternatives, then, are simply extra stress on language--though this is not necessary since it already occurs in stressed (end) position in the clause--or:
You might recognize him by his very language.
You might recognize him by his language alone.
You might recognize him just by his language.
Consider these 325 examples produced by German learners, for analysis or practice: click here.