Most Hebrew words are derived from three-letter root words.
The vast majority of words in the Hebrew language can be boiled down to a three-consonant root word that contains the essence of the word’s meaning. Even if you cannot read Hebrew, you will find that you can get some insight into the meaning of the Bible by identifying the roots of words. If you see the same English word in two different places, but different Hebrew roots are used, this may indicate that there is a different shade of meaning. If the same Hebrew root is used in two different places, the words and their meanings are probably related.
A substantial amount of rabbinical interpretation of the Bible is derived from the relation between root words. For example, the rabbis concluded that G-d created women with greater intuition and understanding than men, because man was “formed” (yitzer, Gen. 2:7) while woman was “built” (yiben, Gen. 2:22). The root of “built,” Beit-Nun-Hei, is very similar to the word “binah” (Beit-Yod-Nun-Hei), meaning understanding, insight or intuition.
Similarly, a familiar Talmudic teaching notes the similarity of the words banayikh (your children) and bonayikh (your builders), and suggests that Isaiah 54:13 (and all your children/builders will be students of G-d, and great shall be the peace of your children/builders) indicates that those who study Torah are the builders of peace.
Formation of Hebrew Words from Roots
Hebrew words are formed from roots by changing vowels and by adding a wealth of prefixes and suffixes to that root. Prefixes can be prepositions (in, on, of, to, etc.), articles (the), or other things. Suffixes can be pronouns (he, you, our, etc.), possessives (‘s), or can indicate gender and number (female singular; male plural, etc.). Because of the way these prefixes and suffixes are added to the root, a single word in Hebrew might be translated into English as several words.
For example, the first word of the Torah, “bereishit,” is usually translated as “in the beginning.” The root is Reish-Alef-Shin, which means “head” or “first.” (See Hebrew Alphabet to learn the letters). It is the same root as the “Rosh” in “Rosh Hashanah” (first of the year, i.e., Jewish New Year). We add the prefix Beit, a preposition meaning “in,” “on,” and a number of other things. The word “the” is implied.
A more complicated example is the Hebrew word “shehecheyanu,” the name of a popular prayer recited on holidays and at other times. The single word “shehecheyanu” means “who has kept us alive.” The root of this word is Cheit-Yod-Hei, a verb meaning “to live.” It’s the same root as the Hebrew word “chai” (life or living) which you commonly see on Jewish jewelry, and the Jewish toast “l’chayim!” (to life!) The Shin prefix turns the verb into a noun indicating a person who does the thing (“who”). The next letter is Hei, which normally turns a verb into a causative form (“has kept”). The Nun-Vav suffix is a first person plural pronoun (“us”). Thus, shehecheyanu means “who has kept us alive.” Whew!
Source (and to read more): http://www.jewfaq.org/root.htm