Labeled bracketing

Labeled bracketing is a way of representing the structure of an expression by writing square brackets ('[' and ']') to the left and right hand side of its component parts, i.e. words or constituents. The brackets carry subscripts, so-called labels, which state the category of the unit in question.

Example

the structure of the sentence the boy may eat apples is written as in (i):

(i) [IP[NP[Det the][N boy]][I'[I may][VP[V eat][NP[N apples]]]]]

The bracket notation is equivalent to the representation by means of a tree structure. The labeled brackets correspond to the nodes in the tree. Thus, a labeled bracketing like (ii) is equivalent to the tree in (iii).

(ii)    [NP [Det the] [N boy]]
(iii)	        NP
               /  \
       	     Det   N
             /      \
	   the	    boy

Link

Utrecht Lexicon of Linguistics