When to change -y to -ies, -ied, -ier and -iest

Forming pluralsTo form the plural of a noun, we change a -y ending to -ie- before adding s.baby babieshobby hobbiesfamily familieslorry lorries

Forming the third-person singular of a verbTo form the third-person singular (he, she, it) of verbs, we change a -y ending to -ie- before adding s.fly fliestry triesmarry marriescopy copies

Past tense of verbsTo form the past tense of regular verbs, we change a -y ending to -i- before adding s.study studiedtry triedhurry hurriedmarry married

Comparatives and superlativesWe change the -y ending of an adjective to -ier and -iest to form comparatives and superlatives.happy happier, happiestheavy heavier, heaviestlazy lazier, laziest

Forming adverbsWe form adverbs from adjectives by changing a-y ending to -ily.happy happilyheavy heavilylazy lazily

Be careful!

We don't change -y to i when the word ends in-ay, -ey, -oy, -uyplay playedmonkey monkysenjoy enjoysbuy buys

exception: day daily dayly

Change of y to i: Words ending in y preceded by a consonant, change the y to i and add es or ed.Words: puppy - puppiesarmy - armiessupply - suppliessky - skiesparty - partieslibrary - librariesrely - reliesmarry - marriestheory - theoriesstudy - studiesapply - applies

Words ending in y preceded by a vowel, just add sWords: boy - boystoy - toysemploy - employsvalley - valleysdelay - delaysconvey - conveyspray - praysstay - stays

Adding a suffix: Words ending in y before a consonant usually change the y to i before a suffix.Words: happy - happinessbeauty - beautifulbusy - businessmystery - mysteriousluxury - luxuriousfancy - fancifulenvy - enviousmercy - mercilessordinary - ordinarilyvary - varianceapply - appliance

But some verbs ending in y do not drop the y before ingWords: study - studyinghurry - hurryingrelay - relayingpray - prayingportray - portrayingapply - applying