A phrase is a single unit that functions as a single unit of a sentence. Any group of words, in simple parlance, can be called a phrase. In a sentence there are many stops which can serve as indications of the complete meaning of a sentence. This happens in speech very often. For example; Peter asks Jim, ‘Why don’t you come out more often?’ Peter just replies, ‘a huge wall’. Peter immediately understands that Jim is saying that he has built a wall and is unable to come out of it figuratively. This is something a human being can do as he/she has world knowledge. Computers would struggle to complete sentences as they go purely by what is in the syntax of the text/speech. A phrase is enough to indicate what the speaker wants to convey.
‘Stops’ are also occurrences in ‘Phonetics’ but they serve a different purpose there. In speech we do not follow a linear approach to understand one another. We can make out the meaning just by hearing the phrases. Although in written communication sentences have to be completed, meanings can still be understood by the core units or constituents. These constituents are typically phrases. Phrases generally have an important word determining the linguistic feature of a sentence. This word is the head of the phrase. Then a sentence also has a dependent which is the rest of the phrase other than the head.
The phrase is also called a full subordinate clause but that is only because some linguists are not comfortable with the term phrase as the sentence without formal meaning can be understood only with reference to a context which may not be mentioned. There are rare cases where there may be non-headed phrases. If this is the case then subordinate clauses are phrases. Phrase structures need not be used in online tutoring as they are of specific relevance more so to linguists. Students need to clearly differentiate phrases from other features of a sentence. There are two types of phrases- exocentric and endocentric. Exocentric phrases don’t have a head and endocentric phrases have heads. The method of introducing a constituency tree is useful in determining the various features of a phrase. A noun phrase has a noun as its head word. It is also called nominal phrase. ‘Present financial crisis’ is an example of a noun phrase. A verb phrase has one verb and the dependents of that verb. In the sentence ‘John saw the star through a telescope’, ‘saw the star through a telescope’ is an example of verb phrase. By mentioning these details online tutors reinforce each subsequent feature thus strengthening the schema.