r-controlled vowel
A vowel followed by r, where the r changes the vowel's sound, like er, ir, ur.
position-based tendency
A spelling that usually shows up in a certain place in a word: the beginning, middle or end.
suffix
A word part added to the end of a base, like -er, -or or -al.
schwa
A lazy, quiet vowel sound, like the a in animal or the e in camel. It can be spelled with almost any vowel.