The letters qu.

Plumber (silent b), honest (silent h), knowledge (silent k), iron (silent r).

The -ie changes to -y for -ing, and sometimes only -d is added for the past tense (e.g., lie → lying, lied).

When it follows a short vowel sound (e.g., badge, judge).

It can be spelled c, k, ck, ch, cc, qu, q, cq, cu, que, kk, or ke.

Use a word wall or spelling lists. Copy and arrange words in the right order, practice writing using models, transfer information activities, spellingbee

When forming the plural of words ending in these letters (e.g., bus → buses, church → churches).

It contains many inconsistencies between spelling and pronunciation.

Proper nouns, countries, cities, nationalities, languages, months, holidays, and days of the week.

Controlled practice, guided production, free production.