I before E, or E before I?

Lots of people seem to have trouble spelling words that contain the vowel combinations ei and ie. Combinations like these, with a pair of vowels treated as a single syllable, with a simple sound, are called digraphs or monothongs.

I don't know how it's taught in other countries, but in the UK there's a mnemonic, 'i before e except after c'. Since it's only true for some words, it really doesn't help, and may indeed be why so many people have trouble correctly spelling words that include the ei and ie digraphs… 

The bad news is that there's no absolute rule that works for all words with the ie and ei combination, but there is a rough test that can be used to sort out quite a few. (The others just have to be learned or avoided.)

The test is based on the sound the digraph makes (and in the examples below, on British-English pronunciation).

1. If the sound the digraph makes in the word is ee (rhyming with feet), the 'i before e except after c' rule usually works:

• belief, believe, besiege, brief, cashier, chief,* chieftain, field, grief, grievous, lief, piece, pierce, priest, relief, relieve, reprieve, shriek, sieve, siege, thief, thieve, yield

*handkerchief and mischief work like chief, though they are not pronounced with the ee sound for ie

• ceiling, conceit, conceive, deceit, deceive, perceive, receipt, receive

2. If the sound the digraph makes is not ee (a sound other than ee), the spelling order is usually ei:

• eider, eiderdown, eight, foreign, forfeit, freight, heifer, heir, leisure, neigh, neighbour, reign, rein, skein, sleigh, their, veil, vein, weight, weir, weigh

3. The irregularities: learn them or learn to avoid them…

• ancient, feisty, fierce,* friend, seize, species, weird*

*strictly speaking, the ei in weird and the ie in fierce are not digraphs but diphthongs (a combination of two vowels that requires the mouth to move to a new shape), but for spelling purposes they can be included in this list

Always use a spellchecker and/or a dictionary to check the spelling if you aren't sure.