Most English words used today were not originally English. These words were adapted from other language, such as Latin and Greek. It can be helpful to know some of these roots of English vocabulary. It may be possible to guess the meaning of an unknown word when one knows the meaning of its root. Knowing prefixes and suffixes can also help.
An English word can consist of three parts: the root, a prefix, and a suffix. The root is the part of the word that contains the basic meaning, or definition of the word. The prefix is a word element placed in front of the root, which changes the word's meaning or makes a new word. A suffix is a word element placed after the root, which changes the word's meaning as well as its function.
When adding a suffix to a one-syllable word, if the root word ends in only one consonant and has only one vowel before it, and if the suffix begins with a vowel, then the consonant ending the root word will be doubled. For example, when adding -ing to can, we double the n to end up with canning. The rule for multisyllable words is the same, but applies only when the last syllable of the root is accented, like in beginner and concurring, but not in begins or forgetful.
For words ending in silent e, when the suffix begins with a vowel, that silent e is usually dropped before adding the suffix. For example, in take and -ing, we drop the silent e off of take, then add the suffix, and end up with taking.
When adding a suffix to a word ending in y, if there is a vowel before the y, just add the suffix. For example, obey + -ed becomes obeyed. If there is a consonant before the y, we will usually change the y to an i before adding any suffix (except -ing and -ish.) For example, angry + ly becomes angrily, and baby + -ign becomes babying.
Worksheet (PDF): Adding suffixes to words ending in 'y'