Theory of Translation 1 Introduction

(II) Class Shifts
: While defining ‘class’, Catford quotes Halliday, who defines class 
as “that grouping of members of a given unit which is defined by operation in the 
structure of the unit next above” (p. 145). Catford explains that class-shift occurs 
when the translation equivalent of an SL item is a member of a different class from 
the original item. Because of the logical dependence of the class on structure (of the 
unit at the rank above), it is clear that structure-shifts usually entail class shifts, 
though this may be demonstratable only at a secondary degree of delicacy. 
(III) Unit Shifts
: By unit-shift, Catford meant changes of rank. Catford defines unit 
as “stretch of language activity which is the carrier of a pattern of particular kind”. A 
unit shift is departure from formal correspondence in which the translation equivalent 
of a unit at one rank in the SL is a unit at a different rank in TL. 
(IV) Intra-system Shift
: Catford uses the term ‘system’ for a finite set of alternants 
among which a choice must be made, e.g., the system of number. When two 

---

58 
languages have a formally correspondent system, but choose a non-corresponding 
item as translation equivalent, an intra-system shift occurs. In this case, the shift 
occurs internally, within a system. It happens in those cases where TL and SL possess 
system which correspond as to their constitution, but when translation involves 
selection of a non-corresponding term in the TL system (p. 147). 
Thus, Catford studies and formulates translation shifts exhaustively. Although his 
analysis has been later described to be confining solely to linguistics, it is notable that 
Catford was the first theorist to use and define the term. Prior to Catford’s theory, the 
changes occurring in translation were looked down as gaps, or even mistranslations. 
According to Bassnett, Catford’s research, “like that of Newmark and Nida, laid a 
foundation for translation studies to evoke as a discipline” (Studies, Preface, 3).