I found I had to install the Polish language version to get all voice packs. It will first start with the UI in Polish, of course, so you'll have to change the text language to English (or whichever you want the UI and subtitles in).
I think that's the only way with the latest version. CDPR used to provide voice packs before the 4.x content update, but they don't appear to provide any for 4.x