Certain minor peculiarities of language are used unconsciously by poets  If such peculiarities appear in the works of more than one poet, they are likely to reflect the language in common use during the poets' time  However, if they appear in the work of only one poet, they are likely to be personal idiosyncrasies
As such, they can provide a kind of fingerprint that allows scholars, by comparing a poem of previously unknown authorship to the work of a particular known poet, to identify the poem as the work of that poet
A peculiarity of language that might be used as an identifying mark is likely to be widely scattered in the work of a poet, so that a single poem not known to have been written by that poet might not include that peculiarity.