Question

By analogy with the oxoanions of sulfur, H2TeO3 would be named?

Answer 1

Tellurous acid. The salts would be called tellurite.

When an element has two oxidation states (valencies) the lower one has an -ous ending and the higher one an -ic ending.
The salts of these acids are called -ite and -ate respectively.

Sulfuric acid `H_2SO_4` vs. sulfurous acid `H_2SO_3`
Sulfate `SO_4^(2+)` vs. sulfite `SO_3^(+2)`

This used to be common also with metal ions:
Iron(II) used to be called ferrous
Iron(III) used to be called ferric

There is a problem when there are more than two possibilities. In this case the prefixes hypo (=under), (hy)per (=above) could be used, like with the oxo-chlorin anions:

`ClO^-` hypoclorite
`ClO_2^-` chlorite
`ClO_3^-` chlorate
`ClO_4^-` (hy)perclorate

The official names for these are now:
monoxo-, dioxo-, trioxo- and tetroxo- chlorate.