2.1. The uses of annotating segments¶
In Orange Textable, an annotation is a piece of information attached to a segment. Annotations consist of two parts : key and value. For instance, in the now classical case of the word segmentation of a simple example, segment simple could be associated with the annotation {category : adjective}; this annotation’s key is category and its value is adjective .

Figure 1 : Annotating simple as an adjective.¶
A segment can have zero, one, or several annotations attached to it. The same segment could be simultaneously associated with another annotation such as {word type : lexical} , or any {key : value} pair deemed relevant.

Figure 2 : Segments with various annotations¶
Note that annotation keys are unique : Since they serve to recognize various annotation values attached to a single segment, annotation keys cannot be duplicated within the segment. On figure 2 above, simple can only have one value at a time for key category.
Even though they have been ignored so far in this tutorial, annotations play a fundamental role in text data processing and analysis. They make it possible to go beyond the basic level of forms that are “physically” present in a text and tap into the interpretation of these forms–which is often more interesting.
For instance, the texts composing a given corpus could be annotated with respect to their genre (novel, short story, and so on), and the parts of these texts might be annotated with regard to their discourse type (narrative, description, dialogue, and so on). Such data could be exploited to study the distribution of discourse types as a function of genre, which would be at best extremely difficult, if ever possible, without having encoded the relevant information by means of annotations.
Whenever Textable widgets manipulate text contents, they can manipulate annotations instead: you can search for segments attached to specific annotations, count annotations, merge data based on their annotations, etc.
There are several ways of creating annotations in Orange Textable. In the following section, we will see a simple method based on the Merge widget. Later on in the Tables section, we will discover various ways of exploiting such annotations.