What is alignment? Some definitions…
Alignment: a process that matches up a source text and the target text segment by segment into translation pairs, which will be stored up in a database to be used as a translation memory. Alignment makes it possible to reuse previous translations in future translations. Human input is required in alignment operations.
Alignment tool: translation software for the creation of bilingual text databases where sentences (or phrases) of source texts are linked to corresponding text segments of a target language.
Segment: a predefined unit of a source text that can be aligned with its corresponding translation in a machine or machine-aided translation system.
Segmentation: refers to sentence separation in a machine translation system, the purpose of which is to divide a text into easily manageable segments. Segmentation is unnecessary in some languages, but important in others. In the case of Chinese, one of the most intriguing issues in Chinese-English translation is the problem of segmenting the Chinese source text as there are no interval markers, or word boundaries, between two successive characters or phrases in a Chinese sentence.
Source: A Dictionary of Translation Technology, Chan Sin-wai, The Chinese University Press, 2004
What is alignment?
Alignment is the process of binding a source-language segment to its corresponding target-language segment. The purpose of alignment is to create a new translation memory database or to add to an existing one. The corresponding pairs of source and target-language segments are called “translation units”. Once the translator has loaded the parallel texts—an original and its translation—into the system, the tool makes a proposal for aligning the segments based on a number of algorithms such as punctuation, numbers, formatting, names and dates, for which the translator is offered various choices. The translator can then adjust the alignment proposed by the system before committing the aligned texts to the memory, either by creating a new one, for ex., for a new subject field or new client, or by adding to an existing one. Translation units are usually numbered or tagged. The collection of translation units is stored, in no particular order, in the database for future translations. Most commercial alignment tools allow alignment at the sentence level. However, in recent years the attention of researchers is also focused on alignment methods for translation memory systems below the sentence level.
Source: Translation and Technology, C.K. Quah, Palgrave Macmillan, 2006
What is alignment?
Alignment is the process of comparing a source text and its translation, matching the corresponding segments, and binding them together as translation units in a TM. For the best results (automatic alignment), the source and target texts must have a similar, if not identical, structure.
Alignment is the process whereby sections of the source text are linked up with their corresponding translations. Alignment can take place at many different levels: text, paragraph, sentence, sub-sentence chunk, or even word. Most bilingual concordancers align texts at either the paragraph or the sentence level. Alignments at text level are too high-level to be useful for helping translators find an equivalent for a particular expression, whereas alignment at word level is notoriously difficult and error-prone given the lack of one-to-one correspondence between most natural languages.
Source: Computer-Aided Translation Technology, Lynne Bowker, University of Ottawa Press, 2002