By changing one letter

[WhyCantIuseTheNameIWant]

You change a name totally.
Brendan is probably an adult name, but Brandon is more likely to be a child.
Brendan probably a middle aged man, but drop the n, Brenda is a lady.

Bryan is a man name, but Ryan is quite popular for a boy.

What makes a name girl or boy?

Ryan, Bryan, Ian, dan, Dylan... All end in "Anne" but "Anne" is a girl name...

I don't get your point but your post really made me laugh

I am not sure i had a point... Only similar names being very different.
If that makes sense?
Glad I made you laugh. I was hoping to make somebody think!

Consider your mission accomplished! It's not just names either. Lots of words in the English language are similarly confusing. It's often down to the history of the word and the word being borrowed from or based on other languages

bI kind of know what youre getting at. Gracie and Jordan are names parents would choose for their babies but seldom will you find any baby Gordon or Tracie's and it is just one letter which differenciates them.

I know a Gordon whose grandson is Jordan!

but brendan to brandon changes 2 letters!

Oops. Sorry. I can't count. Or spell. Or both?