particles - Rosetta Stone uses は instead of わ

Just started learning Japanese again. My college offers no class on this so I am learning on my own. I have been using Rosetta Stone on and off again for a while now.

One thing I have noticed is that Rosetta Stone uses は and を in basic sentences such as:

おんなのひとは、おちゃをのんでいます

This sentence gives the Romaji:

onna no hito wa ocha o nonde imasu

Now I know

• は = ha


• を = wo

Why would they use those in place of わ and お?

Answer

When being used as a grammatical particle ([助詞]{じょし}), は is pronounced わ (wa), を is pronounced お (o), and へ (which you may not have come across yet) is pronounced え (e).

I've never used Rosetta Stone but it seems quite strange that it would not mention this...

Information as to the historical reason for this difference between spelling and pronunciation can be found in the answer to this question.