This study investigates jargon sociolinguistically. It examines jargon use within the context of situation by workgroup members in Mosul. Although workgroup members speak Mosuli Arabic (MA henceforth), it has been noticed that there are some terms, used by them, that are usually hardly understood by outsiders (the public) or even not understood. These jargon terms are supposed to be used for certain purposes, and the current research tries to shed light on the use of jargon by analysing six naturally-occurring dialogues that are recorded through non-participant observation. Since this study is conducted for the first time in Mosul, there is no ready-made corpus, and in order to be authentic and reliable the data of the study are collected by the researcher herself, though the data are said to be primary data. The data are collected from the field (context of situation) of six selected occupations, three of them are professions represented by physicians, electric engineers, and IT programmers. On the other hand, the other three occupations are crafts represented by goldsmiths, car mechanics, and construction workers. The speeches are analysed depending on Hymes' S.P.E.A.K.I.N.G. Model to find out the main uses of jargons.