What is GATE?

GATE is a open source free software used for computational task which involves human language. This can be extensively used for processing of textual content and hence the name General Architecture for Text Engineering (GATE). The main concept of GATE is centered on “Annotations” on different levels like token annotations and sentence annotations. Annotation is about adding “metadata” information to other information. It is a methodology for adding information to a document at different level, where the information can be about a word, sentence, paragraph or the entire document, and annotation is grounded to particular point in a document.
The purpose of annotation differs from a case to another, we can use annotation for a documents classification task, or a comparison task. We might also use it to correct documents without changing them. Sometimes, we use annotation to extract some information that we need, annotation approach helps us to avoid reading the entire document.

https://gate.ac.uk/