No language ever stands still. The English language is a dynamic, living thing, and that means rules of grammar can and do change over time. Words become archaic; rules of grammar change; even spelling and usage change over time.
There are many areas where English is in transition right now. A few of them are outlined below.
"Nauseated" and "nauseous."
Originally, "nauseated" meant "sick to your stomach;" if the smell of tuna fish turns your stomach, you can say that tuna makes you nauseated. "Nauseous" meant "causing nausea in others." If you are "nauseous," that means you make other people sick. However, these two terms are used interchangeably so often that some references are now beginning to list "nauseated" as a synonym for "nauseous."
"All right" is generally more acceptable than "alright."
"All right" means "okay." Literally, "all is right." It's not one word. This rule is beginning to bend, though; the newest Oxford English Dictionary lists "alright." I get a lot of email, pro and con, on the acceptability of "alright," which is further confused by the fact that some dictionaries and books on English usage still condemn it, while others have begun to accept it.
"Judgment" is generally more acceptable than "judgement."
Traditionally, one who judges another is said to pass judgment. Increasingly, more and more reference texts are listing "judgement" as an acceptable variant to "judgment," though not everyone finds "judgement" acceptable.
I personally prefer "judgement," as I think it's more logically consistent. Other words ending in the letter "e" keep that "e" when adding a -ment suffix (as in "atonement," for example); and the word derives most immediately from the Middle English jugement, so keeping the "e" seems reasonable to me.
"Sneaked," not "snuck," is generally the preferred past tense of "sneak."
In formal or professional writing, it's generally considered more proper to say "the burglar sneaked into the room" than "the burglar snuck into the room." However, this rule is also beginning to bend; my dictionary considers "snuck" an acceptable, but less preferred, past tense form of "sneak."
To me, "snuck" sounds clumsy. While I'll grudgingly accede to the fact that it's a very common usage, that doesn't mean I have to like it!
"Interface" is properly a noun, not a verb.
An interface is a place where two different things come together or interact with each other. A physicist might talk about how light diffracts at an air-water interface, meaning the point where the air meets the water; a computer technician might speak of an interface where a printer is connected to a computer; a computer programmer might speak of the interface that a program presents for interaction with a person.
The first time I heard the word "interface" used as a verb (as in "Let's see if we can get this database server to interface with this client"), I cringed. Then I heard the word "interface" used to refer to interactions between people (as in "Let's see if we can have our sales reps interface with the design department on that issue"). Ugh!
This usage is becoming common enough now that some dictionaries have begun listing "interface" as a verb.
Indeed, modern English in popular usage seems to be moving more and more in the direction of blurring the line between nouns and verbs; I saw a bumper sticker a while ago reading "Stop Noun Verbification: Don't Verb Your Nouns."
Commas in lists
In the past, a list of words or phrases separated by commas would include a comma after each word or phrase in the list: "I like apples, peaches, pears, and bananas." Today, it is becoming increasingly common to omit the comma before the second to last word in the list, and indeed this is the preferred usage according to some style manuals: "I like apples, peaches, pears and bananas."
However, this new usage creates potential ambiguities. As a friend of mine recently pointed out, in a sentence such as "I am an expert at hardware design, software and firmware validation, analysis and reverse engineering of products, and user interfaces," that final comma is essential to making the sentence comprehensible. Under the newer preferred usage, the sentence would read "I am an expert at hardware design, software and firmware validation, analysis and reverse engineering of products and user interfaces." Without the comma, it seems as though "analysis and reverse engineering of products and user interfaces" means "analysis and reverse engineering of products" and "analysis and reverse engineering of user interfaces"--that is, it is not clear that "analysis and reverse engineering" applies only to "products" and does not modify both "products" and "user interfaces."