[name]Theo[/name] and [name]Theodore[/name] are strong names in our boy list. We’ll probably go for [name]Theo[/name] because the baby’s last name is long and sometimes tricky to pronounce.
However, we have big sister [name]Tessa[/name]. I like the names separately but put together they sound…a bit too matchy? What do you think?
I don’t think they sound matchy. Although they have letters in common, they don’t contain any of the same sounds.
I agree with pp. While they look similar when written, they have very different sounds. Maybe you could go with [name]Theodore[/name] for a full name so they don’t look as alike when you see them written together.
[name]Tessa[/name] and [name]Theodore[/name] nn [name]Theo[/name] are so cute together!
Ditto! I love your daughter’s name, and I love [name]Theodore[/name]/[name]Theo[/name], too! 
Good luck!
These are two of my favorites, and I think they sound great together!
Unless you’re from a country where they say [name]Theo[/name] with a T instead of a TH (that is, like Teeo or Tayo), they don’t share any sounds.
I agree with everyone–[name]Tessa[/name] and [name]Theo[/name] are not matchy at all, and a wonderful sib-set!