English names are confusing. Take, for instance, the name of a Saint who's feast has moved three times since the Second Vatican Council: Saint Jane Frances of Chantal (Jeanne Françoise de Chantal).
How is Jeanne to be translated?
We say Jane of Chantal but Joan of Arc for the same Jeanne. There is also Joann(e) and Johanna, all of which come from the same Latin root word Iohanna.
To avoid all the confusion the English language should simply leave proper names the way they are originally, spelling and saying them as their owners and originators intend(ed)! Or, at least use the Latin (as the Germans do with most names: e.g. Johanna). But, please, let's be consistent! If we say Jane of Chantal we must say "Jane" of Arc; and vice versa, if it's Joan of Arc it must be "Joan" of Chantal!
It always gets me when we say "Charles" (a French name!) for Carlo on the feast of Saint Carlo Borromeo. Of course, in the Spanish Missal we say "Carlos."
Welcome to English eclecticism!
On this matter of names there is a norm for the choosing of a name, in the traditional Ordo of the Baptism of Infants, which is today almost universally unknown.
70. Since a name is given to those who through baptism are to become children of God, newly born in Christ and enrolled in His service, let the priest see to it that ugly, notorious, or ridiculous names are not imposed, nor those of false deity or heathen profligates. Rather let names of the saints be selected so far as possible, whose example the faithful may devoutly imitate and to whose patronage they are consigned.
N.B. In my Hispanic parish community I recently met a "Hitler." We would do well to go back to that norm.
N.B.B. The Gospel records Our Blessed Lord changing one man's name (and that of man only!): "Simon Bar-Jona...I say to thee: That thou art Peter ("Rock"); and upon this rock I will build my church, and the gates of hell shall not prevail against it." Matthew 16:18
That fact alone should make the who world Catholic (following and venerating the Pope: Peter). That is why Popes choose a new name upon receiving the office of Peter, because their reality changes when they are made Vicar of Christ and head of His Church. Jesus Christ changes them, so they take a name to signify the change. The Vicar of Christ represents Christ and thus weds the Church on earth in His name.