A system for automatically producing a sentence structure diagram for each analysis of a given sentence has been added to the program of the multiple-path syntactic analyzer. A structure code, consisting of a series of structure symbols or phrase markers that identify the successive higher-order structures to which the word in question belongs, is assigned to each word of the sentence. The set of structure codes for the words of a given sentence is equivalent to an explicit tree diagram of the sentence structure, but more compact and easier to lay out on conventional printers. The diagramming system makes some experimental assumptions about the dependencies of certain structures upon higher-level structures. All the major syntactic components of a sentence (i.e., subject, verb, object, complement, period, or question mark) are represented in the current system as occurring on the same level, all being dependent on the topmost level, “sentence”. A floating structure such as a prepositional phrase or adverbial phrase or clause, whose dependency is not determined in the analyzer, is represented as depending upon the nearest preceding structure modifiable by such a floating structure. Different assumptions as to structural dependencies would yield different diagrams without requiring modification on the main flow of the diagramming program. The diagrams thus obtained contribute greatly to the rapid and accurate evaluation of the analysis results, and they are also useful for obtaining basic syntactic patterns of analyzed structures, and for detecting the head of each identified structure.