Why did Darth Vader develop a British accent?

This has always been something which bugged me from an IU perspective. Even though the OOU reason iis obvious, I wonder how to reconcile this IU.

iIn Obi Wan Kenobi, we head unmasked Vader’s unmodulated voice and it’s the same as Hayden’s Canadian accent:

Yet in ROTJ, unmasked Vader has the English accent of Sebastian Shaw. Now one could argue that he doesn’t really sound distinctively English, but IMO he clearly doesn’t sound Canadian or American at all. Shaw has a very esteemed gravitas to his voice and sounds English IMO:

What is your head canon for the IU reason as to why his accent would change?

@frozen: I guess he just got older, and more "dignified" as he did so.

Lol I can see that.

His daughter seemed to do so as well.

@nassergrant19:

Leia had that weird fake British accent in ANH but it’s fully gone in ESB and ROTJ. And the sequels.

Commonly reported side effects of Bacta include: diarrhea, dizziness, drowsiness, dyspepsia, fatigue, insomnia, loose stools, nausea, tremor, headache, paresthesia, anorexia, decreased libido, diaphoresis, and xerostomia. Other side effects include: abdominal pain, agitation, pain, vomiting, anxiety, hypouricemia, malaise, and mutating vocal chords, leading to tone changes and perceived accents.

Too much genocide leads to a british accent.

Anakin’s obviously disappears when he becomes a force ghost tho.

@nassergrant19:

Yeah but as unmasked Vader it was British.

Also his dialogue in SOTS is way closer to Shaw than Hayden, even though he’s described as looking like Hayden.

Most in the Empire had a British accent. Maybe he simply picked it up after being around them for three decades.

Yea

Two decades but yeah, maybe he was also trying to distance from his former self as a coping method.

It was most likely the mask's voice modulator