This book contains among other things, developments of ideas suggested in my papers "Pseudo-units in phonetics" and "On linguistic terminology" read to the Congresses in Prague and Bucharest (both 1967) and in my book Linguistische Ein heiten im Rahmen der modernen Sprachwissenschaft (1966), which, in its turn, includes ideas contained in previous papers. It is my belief that units and relations between units are the basic linguistic facts to be described. Units must be defined in relation to other units, i.e. as elements of systems. Relations or systems contain as elements units having some...