When trying to learn Japanese, one of the many things I experimented with was watching American TV dramas in their dubbed versions. I quickly abandoned this practice, though, because even with very limited proficiency I felt there was something odd about the 吹き替え (fukikae, dubbed) Japanese that came out of the mouths of all those "Beverly Hills, 90210" folks, Ally McBeals, Rachels, Monicas, Phoebes and whatever their names were.
Twenty years later and with slightly improved Japanese language skills, I still have the same feeling, but a somewhat clearer idea of how it comes about. At the heart of the matter is a special register called "translationese," or, in Japanese, 翻訳調 (honyakuchō), that is reserved for Japanese renditions of foreign speech — and that is rather remote from how Japanese is used in real life.
One of the main features of translationese is its heavy use of gendered language, particularly for female characters. It seems that foreign women of all ages, when dubbed into Japanese, have to get their speech marked as hyper-feminine. The easiest way to do so, apart from an unnaturally high vocal pitch, is through sentence-final particles, so-called 終助詞 (shūjoshi).