Akh-zo
* Akh: The "ch" sound is similar to the "ch" in "Bach" or "loch," but slightly softer.
* zo: This sounds like the "zo" in "zoo" or "zero."
It's important to remember that "ach so" is a German expression, and the pronunciation can vary slightly depending on the region or individual speaker. But the "Akh-zo" pronunciation is the most common and widely understood.