We use language every day and we live in a world of words. Hardly any moment passes with someone talking, writing or reading. Indeed, 41. ______ languages is most essential to mankind. Our lives increasingly depend on fast and successful use of language. Strangely enough, we know 42. ______ more about things around us than on ourselves. For example, language 43. ______ is species specific, that is, it is language that differs human from 44. ______ animals. However, we do not know yet how exactly we inquire language 45. ______ and how it is possible for us to perceive through language; nor we 46. ______ understand precise the relationships between language and thought, 47. ______ language and logic, or language and culture; still less, how and when language started. One reason for this inadequate knowledge of language is that we, like language users, take too many things for granted. 48. ______ Language comes to every normal person so naturally that a few 49. ______ of us stop to question what language is, much less do we feel the necessity to study it. Language is far more complex than most people have probably imagined and the necessity to study it is far greater than some people may have assured. Linguistics is a branch of science which 50. ______ takes language as its object of investigation.