N.B.,

It's worth hopping on to this that only #testosterone affects one's voice.

So, while voice will naturally deepen to varying degrees for trans mascs, #estradiol cannot affect voice at all for trans fems.

Whenever you hear a trans fem person with a more-feminine voice, that's usually all entirely through voice training / therapy, as only a handful of folks can afford #VocalFeminisationSurgery (#VFS).