In traditional English grammar, words and sentences (morphology and syntax) were
considered as two basic grammatical elements that built up the grammar theory and most of
studies about grammar were set around these two phenomena. However, right from that time,
there have also been new linguistic issues indicating the fact that there are other linguistic
items lying between words and sentences, even overlapping these two items, or lying beyond
sentences. The need for studies about those phenomena has led to new schools of grammar
with more reasonable concepts established. According to these concepts, apart from words and
sentences, phrases are also one of the most essential linguistic factors in the grammar of the
English language.
A phrase is a syntactic construction which typically contains more than one word, but
which lacks the subject-predicate structure found in a clause(David Crystal – The Cambridge
Encyclopeadia of the English Language, 1995). So, a phrase is just a group of words forming a
grammatical unit which can appear in different places in a clause or a sentence and hold
various functions one of which is apposition whose function indicates the relation between
two or more phrases (appear in the same clause or sentence) of the same reference and the
same grammatical status. In fact, when studying English grammar, appositive phrases are not
focused as much as the other phrases. Moreover, they are sometimes mistaken to relative
phrases which cause lots of difficulties to language learners. A detail study about appositive
phrases, therefore, may partially deal with those problems and suggest some ways of acquiring
and applying the so-called English appositive phrases.