It should become available after the WvW Rush event ends! Sorry for any concerns about missing out on another weapon :)
It's not just the translation. In the English version, the same story or event will have various lines missing on replays. For example when doing dragons end meta, sometimes aurene can talk but nobody else has a voice and other times she's the mute one.
Last week I was helping my bf with a story instance fight getting the timed achievement and I could hear every voice line but he could only hear his commander's lines, none of the npcs.
It's situational and weird.
You may want to try moving the sound quality slider in the audio options tab all the way to the right (highest quality). Folks have reported in the past that having it on the left (fastest) can cause some things to drop or lose post-processing effects.
https://www.reddit.com/r/Guildwars2/comments/opkdu9/voice\_acting\_cutting\_out\_all\_the\_time/
I checked with our Loc and VO folks. The VO has been recorded and delivered. We're in the process of integrating it with a future build. I don't have a hard date on when it'll be live but it's coming.