Most linguistic scholars are in agreement that by 2100 the English langauge (prodominatly American) will in no way be recognizable to a person from our current time. There are two main schools of thought, but first a small lesson concerning english.
While most lanaguges contain 100,000 words, english has no less then 300,000 words. This is because of how adaptable the english lanague is, being a mixture of Germanic, Celtic, and Latin.
English, while constantly evolving, does maintain certain lingustic characteristics. One is that over time English has sped up. In 1200 it was almost rythmic DA---DUM----DA---DUM. Elizabethain times had more along the lines of DA--DUM--DA--DUM. Today, while some distincive subdialects, like the black english vanacular, and Spainglish are at a pace completely diffrent, it is DA-DUM-DA-DUM.
Some speculate that the speed a which English is spoken will be even faster, and resemble almost 1984's new speak, but langauge will shrink due to convienance and not dumbing down the populace. And littered with slang.
Example: Billy, and I will go to the store tommorrow. We will get milk, cheese, and bread.
Men'billywillgotadastoreangetsmilkcheeseanbread.
Another school of thought is that english will simply become slang, and anyother langaue close to its development (IE Spainish). So while maintianing the spacing with a slight change, the 300,000 + words would drop, and be replaced by more broad terms. Good,great,super,excellent,gravy= a single slang word.
And if this sounds like totalt crap send me a message and I'll explain it fuller.