Idia generally talks with a stutter in the original game, which was removed from the English-language adaptation of Glorious Masquerade.
This seemed like a language limitation, but his stutter has been accurately recreated on EN in other places.
This resulted in lines like “Blue handkerchiefs…ah, ah, th-th-the glass mobiles seem to be less simple than these…” becoming “Plain blue handkerchiefs? Um, no offense, but these look way more basic than those glass mobiles…” and “B-b-b-but then…” becoming “Okay, but, like…,” making the EN adaptation of Idia maybe sound more assertive than the original.
There are theories that English-language translation for the game might be separated into multiple teams. It is possible that the localization team assigned to events like Glorious Masquerade is different from the team that did Idia’s vignettes, which would explain the inconsistency in his speech patterns.
Idia is often repeating the line “Leave it to your big bro (nii-chan),” which is extremely important.
We see that he used to say it to human-Ortho when they were children, and it uses the nii-chan variation of “big brother,” not robot-Ortho’s “nii-san.”
That means that every time Idia says it, he is invoking human-ortho.
But it seems Aniplex USA might not have known this about the character until the same time as the players: when they got to Book 6.
As a result there are earlier instances (Book 5 and Ortho’s ceremonial robes vignette) where Idia says his oft-repeated line and it was either rewritten or just removed entirely from EN.
Twisted Wonderland Reference Note 