I've noticed after watching a lot of anime that sometimes "Watashi wa" sounds like "Wataxi wa" or maybe "Watakshi wa." The instances I've heard the latter were always from females. I was wondering if there's a different accent, dialect, or linguistic custom behind this pronunciation? Thank you.
For example, I heard it at 4 minutes 20 seconds into the video here:
http://gogoanime.io/basilisk-episode-14
(I used the top link). It also happens again at about 4m 38s.