Abstract
Two new perspectives are introduced in this paper. One is concerned with the theory of investigation of linguistic change. The new concepts of "memory time" and "space time" are added to the conventional distinctions of "real time" and "apparent time". The second is a method to display survey results based on memory time. This technique allows us to overview a wide area by appropriately arranging several Glottograms. An analysis of address terms for "father", otoosan, indicated that terms used in childhood in "memory time" are quite different from present address terms. Theoretical considerations follow based on this data.
