Differences between literature in english and English literature?

Languge concerns with its syntax structure, grammatical rules. Literature is about written material in english. Studying languge we must know the grammar structure whereas studing literature means read or write Novels poetry drama.

Literature in English is literature which is translated in English. It can be German, French or any aither literature translated in English. 

English Literature is the literature created by English people.

All English Literature is literature written in English. 

English Literature is a very broad term.  Depending on context it can mean literature written by an English person in a style that is part of a certain tradition; or it can mean most literature written in English.

A university course in English Literature is very unlikely to use only texts written by English people.

"English" is a term with a very wide range of meanings.  In the past, it was sometimes used to describe all the inhabitants of the United Kingdom and also emigrants who had settled in other countries but retained much of their cultural identity.   This means that much of US, Canadian, Australian, etc literature (in English) could be considered English Literature.

English literature is the literature written by the British showcasing the English lifestyle and culture. This type of literary work is written in English language which is the mother tongue or native dialect of these people. The works written by the English people cover the three genres of literature: Prose, Drama and Poetry.

Literature in English is the literary work that covers all regions or countries of the world, written in English. The literature in this category are: Canadian literature, American literature, African literature, Australian literature, Asian literature and the likes.