Yanumat light (2547 (2004): 19) has studied the demands needed to learn English for specific purposes by an emphasis on functional languages, because different occupations, different languages according to the duties.
Ianumas clear aperture (2547: 19) studied the needs of English language for specific purposes with an emphasis on duty. Because it would use a different language, different duties.
A palanquin, light transparent (2547: 19) study needs in learning English for the purpose เฉพาะโดย focuses on language function. Because of different occupation would use different language function.