How is linguistics a scientific study
When linguists claim that their discipline is the scientific study of language, they have in mind certain principles which distinguish between a scientific and a non-scientific study of language. First, linguistics is objective, that is, it considers all languages to be equal. For a linguist, there are no 'primitive', 'pure', 'beautiful', 'cultural', or 'sophisticated' languages. Objectivity is difficult to attain because language is so familiar to us that we can hardly dissociate ourselves from it. The objective study of language is hindered by various cultural, social and historical misconceptions about certain languages. Linguistics has demonstrated that any language, however 'primitive', or 'underdeveloped' its people may be, is as complex and highly organized as any other language spoken by a 'civilized' people. There is no intrinsically 'richer' or 'purer' language, because each language serves the functions needed by its speakers. The linguist deals with all languages equally with the aim to construct a general theory of the structure of the language.
Second, linguistics is basically an empirical, not a speculative or intuitive, discipline in the sense that it examines specific data (e.g. speech and writing), and proceeds by verifiable and justifiable operations. It relies on observation and experiment, and uses formalized principles and a theory capable of formulation. It aims to analyze the data and make generalizations about the regularities encountered in the linguistic phenomena under study.
Third, linguistics obeys the following canons of science : exhaustiveness, consistency and economy. Linguistics deals with all relevant data, i.e., it analyzes all the facts of language that fall within its scope, and studies systematically every linguistic element from all angles. It allows no contradictory statements and requires that all parts of analysis be consistent with the whole. Repetition is not allowed either, and more economic statements containing fewer concepts or symbols are preferred...