Why doesn't Luigi's voice sound like it used to?

Luigi's voice has actually changed a lot over the last 30 years, and there's a very unexpected reason why! His name starts with a J.

PATREON -   / thomasgamedocs  
TWITTER -   / thomasgdocs  

SOURCES
- Charles Martinet talking about the real time Luigi voice (   • luigi  )
- Write up of above event (https://apptrigger.com/2017/09/07/cha...)
- More Charles Martinet talking real time system (http://www.poisonmushroom.org/2008/09...)
- Julien Bardakoff talking about how he ended up voicing Luigi (   • #TEAMG1 - Direct du 14/11/2018 (2/4) ...  )
This was translated for me by a really really kind twitter user who wants to stay anonymous - thanks so much for your help, though!
- Charles Martinet Luigi’s Mansion 2 interview (   • Charles Martinet EXCLUSIVE Interview ...  )

MUSIC
- All music via Epidemic Sound