Was the first T-800 sent from a Europen country? I understand why all the later versions of the Arnold model sounded like the first one. But why did the first one have a thick accent? The T2 version of Arnold was able to sound like young John Connor when he spoke in the phone booth, and the bad Terminators in T2 and T3 mimic other voices. Was the first T-800 damaged and unable to adapt his voice once he arrived? Is there a canon reason why the first one didn't adopt an American accent to blend in?
A deleted scene from T3 actually explained it.
The scene showed a promotional video from the military R&D showing the development of the new type of battlefield humanoid robots; and the humanoid model was based off of Chief Master Sergeant William Candy (played by you can guess who).
The military brass hated the sergeant's "ya'll" Southern accent, and a military scientist with a deep Austrian accent (played by you can guess who) present at the debriefing said "we can fix it [voice]".
The rest is a (deleted) history.