Changes or 'shifts' often occurs in translation. by 'shifts', we mean departures formal correspondence in the process of going from the source language to the target lanugage. Two major types of 'shift' occur: level shifts and category shifts.
By a level shifts we mean that a source language item at one linguistic level has a target language translation equivalent at a different level. Example of level shifts is sometimes encountered in the translation of the verbal aspects of English. This language has an aspectual opposition – of very roughly the type – seen most clearly in the ‘past’ or preterite tense: the opposition between English simple and continuous (wrote and was writing). In english, the (contextually and morphologically) marked term is the continuous, this explicitly refers to the development, the progress, of the event. The ‘simple’ form is neutral in this respect (the event may or may not actually be in progress, but the single form does not explicitly refer to this aspect of the event).
This refers to unbounded and rankbound translation: the first being approximately ‘normal' or ‘free’ translation in which source language to target language equivalences are set up at whatever rank is appropriate. Usually, but not always, there is sentence to sentence equivalence, but in the course of a text, equivalence may shift up and down the rank scale, often being established at ranks lower than the sentence.
(1) Structure shifts
These are amongst the most frequent category shifts at all ranks in translation; they occur in phonological and graphological translation as well as in total translation.
(2) Class shifts
Class shifts occurs when the translation equivalence of a source language item is a member of a different class from the original item. Because of the logical dependence of class on structure it is clear that structure shifts usually entail class shifts, though this may be demonstrable only at a secondary degree of delicacy.