Java Speech API

The Java Speech API (JSAPI) is an application programming interface for cross-platform support of command and control recognizers, dictation systems, and speech synthesizers. Although JSAPI defines an interface only there are several implementations created by third parties, for example FreeTTS.

Two core speech technologies are supported through the Java Speech API: speech synthesis and speech recognition.

Speech synthesis provides the reverse process of producing synthetic speech from text generated by an application, an applet, or a user. It is often referred to as text-to-speech technology.

The major steps in producing speech from text are as follows:

The result of these first two steps is a spoken form of the written text. Here are examples of the differences between written and spoken text:

The remaining steps convert the spoken text to speech:

Speech synthesizers can make errors in any of the processing steps described above. Human ears are well-tuned to detecting these errors, but careful work by developers can minimize errors and improve the speech output quality. While the Java Speech API 1 relied on the Java Speech API Markup Language (JSML), the newer release utilizes SSML to provide many ways for you to improve the output quality of a speech synthesizer.

Speech recognition provides computers with the ability to listen to spoken language and determine what has been said. In other words, it processes audio input containing speech by converting it to text.

The major steps of a typical speech recognizer are as follows:

A grammar is an object in the Java Speech API that indicates what words a user is expected to say and in what patterns those words may occur. Grammars are important to speech recognizers because they constrain the recognition process. These constraints make recognition faster and more accurate because the recognizer does not have to check for bizarre sentences.

The Java Speech API 1 supports two basic grammar types: rule grammars and dictation grammars. These types differ in various ways, including how applications set up the grammars; the types of sentences they allow; how results are provided; the amount of computational resources required; and how they are used in application design. Rule grammars are defined in JSAPI 1 by JSGF, the Java Speech Grammar Format. The newer JSAPI 2 supports the more recent SRGS format. JSAPI 2 does not offer support for dictation.

...
Wikipedia