ELSD is a learning and speech development app, developed by a company in Korea. The service is currently available for Android mobile users. It can also be used by anyone who wishes to develop their speaking skills, in order to improve their ability to communicate with others.

This service is based on the Common English Language Training System (CEATSS) developed by the British Council and IDP: Learning and Speaking English, which is a program of the International English Union. The system is used to teach English as a foreign language. The goal of the program is to teach English-speaking students how to speak and understand English, as well as to develop their speech skills.

ELSD provides a platform for English-speaking students to practice their speaking and listening skills. It can also be used by anyone who wishes to improve their speaking skills, in order to improve their ability to communicate with others.