A geek of the literature persuasion, whether said literature is originally written in English or not. English geeks tend to become professors or teachers of some type, although many of them actually want to be novelists or poets. Generally these ambitions can be combined. English geeks have read far too many books. Many have read them over and over. These books can be of any type, although classic canonical novels or slender volumes of poetry are among the most common. Most English geeks will have a variety of literary interests, however, which one can see by simply perusing their bookshelves.
And English geeks can never have enough bookshelves. If they need to buy furniture, the bookshelf comes first, then the desk and chair, then the bed (I once slept on the floor for six months, even while on salary). They will get as many shelves as can fit into their domicile, and proceed to stuff them entirely full of books. Often they will organize these into a pattern only recognizable to themselves. Alphabetization is probably the most common method, but separation by author's country of origin, subject, date of publication, literary movement, or a combination may also be used. I personally have entertained the idea of assigning call numbers and cataloging all my books. This is not feasible, however, because there is not enough bookshelf. My shelves are all at least two layers deep, with trade paperbacks stacked sideways as the outermost layer. Organization varies per geek, naturally, and it is not uncommon to find people with haphazard stacking on the floor as their main method.
English geeks will often own multiple editions of the same book, and make excuses for keeping both of them, i.e. "but I really need to compare the two translations!" or "I love my heritage Jane Eyre, but the cover is starting to fall off, and this Penguin edition has such a good introduction". They tend to own a number of style manuals, including Strunk and White's Elements of Style and multiple editions of the MLA handbook. They own at least one book of grammar, and use it. Many can talk about participial phrases or the pluperfect tense without pausing to blink, but others rely solely on their finely honed grammatical instincts. This does not mean that they always speak or write grammatically--many feel that they have earned the right to play with language as much as possible. To this end, you will hear conversations peppered with a variety of slang, or read notes written completely in sentence fragments. Language is not just a tool by means of which to communicate, but a complex organism, constantly adapting and evolving. The fact that they can actually participate in it makes English all the more fascinating: the best way to explore its facets is to use them. So while they may be stigmatized as grammar Nazis, they are in fact almost the complete opposite. They split infinitives or use "they" as a singular gender neutral pronoun with wild abandon.
As a result of their bookly obsessions, English geeks will usually be super-conscious of language usage in everyday conversation. It's like being a cinematographer and going to the movies, but language is in constant use almost everywhere, while movies are not. English geeks can thus consider their area of interest in every single conversation, although this does not necessarily mean they will talk about it. When in conversation with another English geek, however, they may end up laughing at each other's use of strange phrasings or archaisms, trying to find the exact word to fit a connotation, or debating whether a given usage is valid for the meaning intended. The difference between the terms "geek" and "nerd" is a good example. These discussions tend to range over topics from current trends in usage to etymological derivation to examples in other modern languages.
Not to say that there is no difference between an English geek and a language geek: there is a substantial difference. A language geek may have conversations about words and their origins or usage, but they generally do not have the obsession with literature. English geeks will have long, detailed conversations about books or plays or poems, or of a combination of these. They refer to Madame Bovary or T.S. Eliot or Noam Chomsky on a regular basis. They know the canon, usually both literary and theoretical, and can discuss it in detail. They can combine this knowledge with their knowledge of their world, and relate them in a variety of interesting ways.
And they proceed to expound on these ideas through writing. The act of writing is an integral part of the English geek's life: they will seldom spend less than a week without getting some new idea about a problem they've been thinking about or a book they've been reading, after which they will have a pathological need to put this idea down on paper (or screen). This writing is not necessarily based on literature, but on anything they feel the need to think deeply about. It can range all over the place, and into any genre. Since words are so important to them in the first place, it is just as important to be able to put their ideas into words. And the more complex or incomplete the idea, the greater the need to write it out.
The English geek's writing is clear and lucid and says just what they want to say, after appropriate revision. They spell difficult words correctly. They proofread by hand, since Microsoft Word has no concept of actual grammar. Even if they have a terrible time writing papers (i.e. panicking about the assignment and not having a thesis until the night before and then drinking lots of caffeinated beverage to stay up all night), the end result will normally be good. Personal writing is generally more important to them than assigned papers, however. This is not to say that they don't want to explore their literary ideas on paper, but rather that their ideas are more interesting to them than their assignments. Comparing two poems which are always compared to each other is boring, especially if the whole class has to compare the same two poems. The English geek will want to explore something else entirely. The problem is that many teachers don't like people who flout assignments. So the English geek may try to worm around the given topic in a creative way.
This facility in writing seems to come from their vast experience with language, which in turn comes from their love of books and reading in general, which can come from a variety of things. Maybe their parents always had books around, or they discovered early that the book is better than the movie, or they were the kid who took their book to recess to avoid playing foursquare or red rover. I don't think there is one way to define how one comes to books. The fact is that one comes to them, and finds there something that is henceforth as necessary as breath.