With the recent (as in, since I started reading newspapers and watching the news) media focus on the Middle East, a number of print media have translated foreign words and names into English and used the apostrophe within these words.

In English, the apostrophe is used to take the place of one or more letters that are left out of a word or phrase in order to shorten it and write it as it sounds phonetically. Words like this are called contractions. For example, in the word "doesn’t" the apostrophe takes the place of the "o" from the phrase "does not". Spelling it with the apostrophe allows it to appear in print in the same manner as it is spoken (i.e. the "o" sound is not pronounced).

Recently, some newspapers and online media have printed names such as the "Ba’ath party" (incidentally, it’s not Party), using an apostrophe in the name. Following the rules of the English language, I’m forced to ask myself what letter or letters are being replaced by the apostrophe in this instance, and how would the complete name be spelled?

Turning to another example and upon digging deeper I find that the word "Ha'aretz" is actually two words in Hebrew: "ha" being equivalent to "the" and "aretz" meaning "land". English translations usually print this phrase as a single word: "haaretz", "ha’aretz" or "ha-aretz".

Words that are translated and published using a hyphen or apostrophe are done so in order to make it easier for the (assumed uneducated) reader to understand that what they are reading is a foreign word or phrase. If the publisher printed "ha aretz" perhaps the caffeine deficient commuter with his morning paper might think the editor let "ha" slip where "the" should have been.

Update: I've been recently informed that the apostrophe is also used to indicated a glottal stop. If you don't want to read that exhaustive node on it, here's the nutshell version: The glottal stop is a guttural sound that is made when the glottal folds (see glottis, the space between the vocal cords in the throat) are pressed together. For example, the sound made when saying "uh uh". Most of the time English language writers leave this out, as it could appear in many common words. Therefore, my theory that editors leave it in to denote a foreign word still stands, I think.

Sources
http://www.cp.org/english/copytalk/ct042003.pdf
http://www.insidevc.com/vcs/opinion/article/0,1375,VCS_125_2007465,00.html
http://www.calpundit.blogspot.com/2003_03_23_calpundit_archive.html
http://www.canada.com/montreal/montrealgazette/specials/StyleGuide2.pdf