Breakdown of konnichiha.

Questions & Answers about konnichiha.
This is one of the first things learners notice. Normally, は is read ha. But when は is used as the topic particle, it is pronounced wa.
In こんにちは, the final は comes from older grammar where it functioned as that particle, so the modern pronunciation stayed wa.
So:
- normal reading of は = ha
- particle は = wa
That is why こんにちは is read konnichiwa, not konnichiha.