"Flowers bloom in the spring."
Translation:봄에는 꽃들이 펴.
The forms of two different verbs according to Wiktionary (8/6/2020):
- 피다: 피어요 (펴요); 폈어요 ; 핍니다 (meaning: bloom)
- 펴다: 펴어요 ; 펴었어요; 폅니다 (meaning: spread, stretch, expand, unfold, open, straighten, realize, materialize, liberate)
But they are not exactly correct. I went and looked for examples (below) on Naver. That doesn’t guarantee accuracy, but it shows how people are actually using them.
- 벚꽃이 피었어요? (The cherry blossoms bloomed?)
- 여기 꽃은 안 피어있지만… (The flowers didn’t bloom here, but…)
- 오른쪽에 피어있는 노란 꽃 (yellow flowers blooming on the right side)
- 민기 집 주변에도 벚꽃 피었어? (Did the cherry blossoms bloom around 민기’s house?)
- 벚꽃이 펴요? (Are the cherry blossoms blooming?)
- 난 그와 헤어지기위해 바람 폈다. (To get him to break up with me, I cheated.)
- 이거 어떻게 피는 거야? (How do you open this?)
- 그리고 이걸 젓가락으로 펴! (And spread it using chopsticks!)
- 어깨 펴. (Straighten [your] shoulders.)
- 그럼 무릎 좀 펴주세요. ([Please] straighten [your] legs.)
- 나 담배 안펴. (I don’t smoke cigarettes.)
- 나는 우산을 펴 들었다. (I opened up my umbrella.)
- 그것을 너무 얇게 펴 바르지 말아라. (Don’t spread it too thin.)
- 가슴을 펴! (Straighten up!)
- 얼굴 펴! (Look happy! Lit.: face smile)
- Tony의 얼굴을 활짝 펴준 그녀 (she who brought a smile to Tony’s face Lit.: she who made Tony’s face smile widely)
Ostensibly, from the above examples, the Wiktionary meanings aren’t very comprehensive as there are a lot of idiomatic examples in the wild. The forms of the verbs being used also disagrees with what Wiktionary lists. 펴어 is rarely used—almost always 펴 instead. 피어 seems to be used more for flowers blooming instead of 펴, but it’s still widely used, though there may be confusion about the root form of 펴. Hence, there are questions about how to use/spell the verbs:
- 책을 '펴다'와 '피다' (To “펴” or “피” the book)
- '피다'와 '펴다'의 차이 (The difference between “피다” and “펴다”)
- '켜어', '펴어'의 표기 (Notation of “켜어” and “펴어”)
- 책을 폈다 (“Opened the book”)
- 녹음기를 켜 보았다 (“Turned on the audio recorder”)
The points I got from reading them are that:
- “펴” is an short (“준말”) for “펴어.”
- But “가아,” “켜어,” “펴어,” etc. has to be written as “가,” “켜,” “펴,” etc. (“‘가아/켜어/펴어’ 등은 준말인 ‘가/켜/펴’ 등으로 표기해야 하며…”)
- Don’t trust Wiktionary all the time.
There are some additional meanings for 피다 (besides bloom) on Naver that I find very poetic an illustrated in the examples:
- 얼굴이 피다: to look great
- 미소가 피다: to put a smile on
(This 2020 update better late than never; old post below: ↓)
- 피다: to bloom
- 펴다: to spread
The the existence of 펴다 keeps the ㅣ apart ㅓ in the 피어 as a disambiguation mechanism.
피- + -어 can be contracted to 펴 and Koreans do write this way. It is neither informal nor inappropriate. You are confusing this with 사귀다 or 바뀌다.