There is a particularly noticeable difference in phrasing in the bracha of the middle section of the Amidah on Shabbat (The bracha that ends מקדש השבת).
Nusach Ashkenaz says ושמחנו בישועתיך - "Gladden us with your salvation"
Nusach Sefard says ושמח נפשינו בישועתיך - "Gladden our souls with your salvation".
What is meant in both versions by the "salvation"? From what or whom?
Nusach Sefard seems more "specific" by mentioning the soul. Why the difference in language and what is meant by mentioning the soul? Is this a reference to the "נשמה יתירה" (additional soul) that Jews receive on Shabbat, or something else is meant? And, why would the happiness of the salvation be restricted to the soul? (I.e., what might Nusach Ashkenaz be omitting or Sefard adding by (not) mentioning the soul?)