How to pronounce“couldn”in English

couldn't build something equally secure, but because usually there's secrecy involved in building, let's say, a new weapon system,

couldn't fly, they couldn't swim, they couldn't jump between land bridges.

couldn't have come back on land anymore.

couldn't see the genius in quantum mechanics initially, couldn't see the correctness, I should say.

Couldn't go back to the 3rd Royal Tank Regiment, so went back to a different unit.

couldn't criticize the company.

couldn't be built until about 6,000 years ago when there was widespread agriculture, but that turned out not to be true.