Japanese · Pronunciation Guide
i-ku, two beats, and that final u is normally whispered — it can sound like the word ends on a puff of air.
iku
Equal time for both units, with the melody dropping after the first. The rhythmic point is that a whispered mora still occupies its full time slot: even when the u is inaudible, native speakers spend the beat on it, and a word cut short after the k sounds clipped.
Listen: 行く
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公園に行きましょう。
Kouen ni ikimashou.
Let's go to the park.
Listen: 公園に行きましょう。
Free browser voice. Hear it read by a real native speaker inside the LingoDrop app.
公園に行きましょう turns it into 行きましょう, six morae ending in a long o. Between the first ki and the ma, that i is again a devoicing candidate, so the middle of the verb can go breathy while the ending holds a long vowel. It's a nice illustration of Japanese doing two opposite things to duration within one word.
The standard English version is "EE-koo" — a long first vowel, a rounded second, and a stressed opening syllable. Every element needs adjusting: shorten the i, flatten the lips for the u, soften the k so no air puffs out, and then let the final vowel go voiceless. Native speakers barely voice it, but they never rush past it.