When you open a document, SDL Trados Studio prepares it for translation by breaking the document text into segments. The segments can then be compared to segments stored in a translation memory in order to find existing translations for the segments. Segments can be paragraph or sentence length. SDL Trados Studio uses punctuation marks to identify where each sentence ends.
As a general rule, in English, a full stop, exclamation mark, question mark, colon, tab character or end of paragraph mark indicate the end of a sentence when they are followed by a space. A quotation mark (" or ’) or a closing parenthesis ()) may follow the closing punctuation mark and precede the space. A semicolon (;) does not end a sentence.
SDL Trados Studio has language-specific segmentation rules for each of the supported languages.
How to Create a Segmentation Rule