Historically, English is a curious cross between Anglo-Saxon, the Germanic language spoken in eleventh-century England, and the Romance language of the French who conquered England in 1066 AD.
Words generally change forms less than in many other European languages, which makes the tasks of NLP a bit easier. Things that make English more complex, are its unusually large vocabulary, diverse dialects, almost unguessably strange spellings of many words, frequent exceptions to those rules that do exist, and a particularly large number of words that change meaning depending on context. Expressions such as "turn on", "turn off", "turn up", and "turn out" can have several meanings each, making it challenging for a computer system or even a person to understand which was meant.
Because of English's importance in both the business and research worlds, NLP systems are better developed for English than any other language. At Gistology, English receives our top priority for breadth and quality of offerings even while our overall strategy is to serve the languages that other NLP providers don't serve.