English for Specific Purposes, or ESP, refers to learning English because you have a specific need. It can include the area of EPP, English for Professional Purposes.
Survival English for immigrants, English for Hotel Management, and English for Air Traffic Controllers are all ESP.
In the classroom
Asking learners what they need to learn is an important element of ESP classes, as often their language needs and aims are very specific. This data can then be combined with the teacher's analysis of core language and learning needs in order to prepare a syllabus.