Rassdyt

Correction: How could something as simple as having variations in one's speech be a mistake? Especially considering the plot of the series occurring after the Attack of the Clones, in which Jar Jar surely could have gotten more used to speaking in a more formal manner, being among the senators.

Rassdyt

It's a speech pattern common to all Gungans, not just Jar Jar. Every time any Gungan says the word you, they say yousa, even the leaders, who would speak in a 'more formal manner'.