A syntactician is a linguist who specializes in the study of grammar and syntax. In the past these specialists were also referred to as grammarian but this practice has fallen out of favor. To understand what a syntactician truly does, it is necessary to first understand linguistics, as the study of syntax is a subfield of the study of linguistics.
Linguistics is the scientific study of language, either theoretical or applied, and a linguist is someone who studies language scientifically. Theoretical linguistics, also known as general linguistics, includes a number of subfields dealing with words, word order, meaning of words, and word sounds. Subfields of linguistics include semantics, syntax, morphology, phonology, and phonetics. Grammar, once considered a subfield of linguistics, is now generally excluded from this list.
Theoretical linguistics also includes comparison of languages, and the exploration of language history. As fields of study, comparative linguistics endeavors to find universal properties of language, while historical linguistics is aimed at the development of language over time. Applied linguistics is the implementation of theoretical, comparative, and historical linguistics in various areas of practice, such as foreign language study, education, speech therapy, translation, and speech pathology.
In linguistics, syntax pertains specifically to the rules governing the ways in which words combine to form phrases and sentences. Syntax is closely associated with grammar, because grammar governs language structure, which is affected by syntactical rules.
So a syntactician is a linguist who specializes in the study of proper combinations or patterns of words in the formation of sentences and phrases. A syntactician can also be a person who documents and attempts to uncover the motivations for usage standards for a particular language.
As an example, let’s say that a syntactician was presented with a sentence for review. The syntactician would primarily be concerned with the arrangement of the words, and whether this arrangement was orderly, systematic, and complied with standard grammatical and syntactical rules. Still, the syntactician would also be concerned with semantics or word meaning — whether a specific word was appropriate to communicate an idea. If the formation of the sentence were awkward, for example, the syntactician might change the word order or word tense to improve the sentence, but generally, the syntactician would not change the words used.