Style' in Sociolinguistics:-

Style is basically the way we speak a language or dialect of any language, may it be Hindi, English or something else. It is important to see Style in Linguistics view, that means Style is the study of dialect variation of any language used for various places, purposes, interest, time, profession, occupation etc. For example we use some words in Hindi/Urdu that are not formally accepted, the way we speak with our friends in Dhaba is not the way we speak with our elders or teachers, even we speak with our seniors differently in hostels as compare to speaking to them in front of teachers or in seminars. We speak differently with our friends in hostel rooms but speak another way in the same hostel's dining hall. The above examples clearly proves that we change the way of using language speech or dialects according to the situation or timing, even we choose to use a single dialect in many ways by changing its sentence structure to suit with the environment. This use of languages in different styles according to different situation, place,time, people, gender is Known as 'Style' in Sociolinguistics.

Register' In Sociolinguistics:-

 Register in Sociolinguistics is the term used for those 'Styles' that are unique and their usage is closely or directly related to some factors like Special Purpose, Occupation, Situation. we should not get confused or mix up 'Style' with 'Register', both are similar but not same. Register, as the name suggests has some fix use of different types of dialects assigned with purpose or profession etc. For example we can use same style of communication with all teachers but we need to change the style while talking with a Clerk of our post office or the Warden of our hostel, in both the case we will use formal way of talking but still there will be a difference, specially while talking to a literate and an illiterate person. Register is basically a style inside 'Style" which is closely or totally associated to some factors as mentioned above. Personally I found a peculiar difference between Style and Register, I realized that Style is more choice oriented, we have more options of whether to change or remain in the same style of communication but, Register differs in this way as we have less or no choice whether to use or not the 'Registered' dialects. 

Jargon' In Linguistics:-

Jargon is very closely related to Register as it takes birth from the dialect used in Registers. As we know that Register is the style of using speech or dialect associated with some factors like profession, class, etc, accordingly there are some special set of words or morphemes that are fixed to a particular Register, For example the words like Cytoplasm, Cell, Nucleus are related to and are used in Biology, similarly Force, Energy, Displacement are words related to Physics, we normally do not use this word and as they have special purpose and field of usage. Therefore those sets of special and unique terms that are used and are associated with particular Registers are called Jargon in Linguistics.