我是个假诗人

就古典诗歌来讲，英文讲究meter和form。form有sonnet，ballad等。meter也不同，通常是轻音／重音 入 at last （at unstressed，last stressed）。in a sonnet，每行都应该五个这样的unit，一共10个音节(similar to 5 alternate 平仄 pair in Chinese) 。当然还要押韵。英文poem（古典）是看syllable数，not number of words in a line. Some of what I wrote (sonnets) followed the rules, some didn't.
As for haiku, originally it required 575, where each number indicates the number of syllables (not words) in the corresponding line. Later they relaxed the requirement (in terms of syllable count). Right looks like there is a grammatical change or something, but I never delved into it. Classic poems are much more difficult to write.
Of course there are many nonclassic poems that are just as good such as the raven (from Poe). Whitman might be the first who broke the ground in free verse. Certainly there are music and rhythm in those.
ha