http://www.creeds.net/ancient/nicenel.htm
The A.D. 381 version doesn’t appear to be any longer than the A.D. 1546 version. At first I thought the words in brackets are pointing out the differences — but then there is [vivificatorem] where the 1546 version has “vivificantem.” So maybe the words in brackets are acceptable variations.
The A.D. 381 version has “we” instead of “I” — credimus/credo, for instance. The A.D. 1582 version added “invisibilium.” — of things invisible. There are some minor vocabulary differences and grammatical constructions that are different.
I’m fairly certain that Spiritum Sanctam is a misprint.
Et in unum Dominum Jesum Christum, Filium Dei [unigenitum], natum ex Patre ante omnia saecula [Lumen de Lumine], Deum verum de Deo vero, natum [genitum], non factum, consubstantialem Patri; per quem omni facta sunt; qui propter nos homines et [propter] salutem nostram descendit de coelis et incarnatus est de Spiritu Sancto ex Maria virginine et humanatus [homo factus] est; et crucifixus est pro nobis sub Pontio Pilato [passus] et sepultus est; et resurrexit tertia die [secundum scripturas]; ascendit in coelum [coelos], sedet ad dexteram Patris; interum venturus, cum gloria, judicare vivos et mortuos; cujus regni non erit finis.
Et in Spritum Sanctam, Dominum et vivificantem [vivificatorem], ex Patre procedentem, cum Patre et Filio adorandum et conglorificandum, qui locutus est per sanctos prophetas. Et unam, sanctam, catholicam et apostolicam ecclesiam. Confitemur unum baptisma in remissionem peccatorum. Expectamus resurrectionem mortuorum et vitam futuri saeculi. Amen.
But it's the same. C.S. Lewis points out in his book on 16th c. English literature (in the O.H.E.L. series) that in order to translate Latin correctly more English words are needed. Latin is 'pithy' and contains 'much matter in little room'. That, and the tendency of 16th c. writers towards elaboration and repetition, is why you see so many doubled words in the Prayer Book - 'give thee most humble and hearty thanks' - 'our manifold sins and wickedness' - 'thy goodness and lovingkindness to us and to all men'